Energy delivery systems and uses thereof

ABSTRACT

The present invention relates to comprehensive systems, devices and methods for delivering energy to tissue for a wide variety of applications, including medical procedures (e.g., tissue ablation, resection, cautery, vascular thrombosis, treatment of cardiac arrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). In certain embodiments, systems, devices, and methods are provided for treating a tissue region (e.g., a tumor) through application of energy.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 13/386,497, now allowed as U.S. Pat. No. 9,119,649, which is aU.S. 371 National Stage Entry of International Patent Application No.PCT/US2010/043558, filed Jul. 28, 2010, which claims priority to U.S.Provisional Patent Application No. 61/229,178, filed Jul. 28, 2009, thecontents of which are incorporated by reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under CA126087 awardedby the National Institutes of Health. The government has certain rightsin the invention.

FIELD OF THE INVENTION

The present invention relates to comprehensive systems, devices andmethods for delivering energy to tissue for a wide variety ofapplications, including medical procedures (e.g., tissue ablation,resection, cautery, vascular thrombosis, treatment of cardiacarrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). Incertain embodiments, systems, devices, and methods are provided fortreating a tissue region (e.g., a tumor) through application of energy.

BACKGROUND

Ablation is an important therapeutic strategy for treating certaintissues such as benign and malignant tumors, cardiac arrhythmias,cardiac dysrhythmias and tachycardia. Most approved ablation systemsutilize radio frequency (RF) energy as the ablating energy source.Accordingly, a variety of RF based catheters and power supplies arecurrently available to physicians. However, RF energy has severallimitations, including the rapid dissipation of energy in surfacetissues resulting in shallow “burns” and failure to access deeper tumoror arrhythmic tissues. Another limitation of RF ablation systems is thetendency of eschar and clot formation to form on the energy emittingelectrodes which limits the further deposition of electrical energy.

Microwave energy is an effective energy source for heating biologicaltissues and is used in such applications as, for example, cancertreatment and preheating of blood prior to infusions. Accordingly, inview of the drawbacks of the traditional ablation techniques, there hasrecently been a great deal of interest in using microwave energy as anablation energy source. The advantage of microwave energy over RF is thedeeper penetration into tissue, insensitivity to charring, lack ofnecessity for grounding, more reliable energy deposition, faster tissueheating, and the capability to produce much larger thermal lesions thanRF, which greatly simplifies the actual ablation procedures.Accordingly, there are a number of devices under development thatutilize electromagnetic energy in the microwave frequency range as theablation energy source (see, e.g., U.S. Pat. Nos. 4,641,649, 5,246,438,5,405,346, 5,314,466, 5,800,494, 5,957,969, 6,471,696, 6,878,147, and6,962,586; each of which is herein incorporated by reference in theirentireties).

Unfortunately, current devices configured to deliver microwave energyhave drawbacks. For example, current devices produce relatively smalllesions because of practical limits in power and treatment time. Currentdevices have power limitations in that the power carrying capacity ofthe feedlines are small. Larger diameter feedlines are undesirable,however, because they are less easily inserted percutaneously and mayincrease procedural complication rates. Microwave devices are alsolimited to single antennas for most purposes thus limiting the abilityto simultaneously treat multiple areas or to place several antennas inclose proximity to create large zones of tissue heating. In addition,heating of the feedline at high powers can lead to burns around the areaof insertion for the device.

Improved systems and devices for delivering energy to a tissue regionare needed. In addition, improved systems and devices capable ofdelivering microwave energy without corresponding microwave energy lossare needed. In addition, systems and devices capable of percutaneousdelivery of microwave energy to a subject's tissue without undesiredtissue burning are needed. Furthermore, systems for delivery of desiredamounts of microwave energy without requiring physically large invasivecomponents are needed.

SUMMARY OF THE INVENTION

The present invention relates to comprehensive single and multipleantenna systems, devices and methods for delivering energy to tissue fora wide variety of applications, including medical procedures (e.g.,tissue ablation, resection, cautery, vascular thrombosis, treatment ofcardiac arrhythmias and dysrhythmias, electrosurgery, tissue harvest,etc.). In certain embodiments, systems, devices, and methods areprovided for treating a tissue region (e.g., a tumor) throughapplication of energy.

The present invention provides systems, devices, and methods that employcomponents for the delivery of energy to a tissue region (e.g., tumor,lumen, organ, etc.). In some embodiments, the system comprises an energydelivery device and one or more of: a processor, a power supply, a meansof directing, controlling and delivering power (e.g., a power splitter),an imaging system, a tuning system, and a temperature adjustment system.The present invention is not limited to a particular type of energydelivery device. The present invention contemplates the use of any knownor future developed energy delivery device in the systems of the presentinvention. In some embodiments, existing commercial energy deliverydevices are utilized. In other embodiments, improved energy deliverydevices having an optimized characteristic (e.g., small size, optimizedenergy delivery, optimized impedance, optimized heat dissipation, etc.)are used. In some such embodiments, the energy delivery device isconfigured to deliver energy (e.g., microwave energy) to a tissueregion. In some embodiments, the energy delivery devices are configuredto deliver microwave energy at an optimized characteristic impedance(e.g., configured to operate with a characteristic impedance higher than50 Ω) (e.g., between 50 and 90 Ω; e.g., higher than 50 . . . ,55, 56,57, 58, 59, 60, 61, 62, . . . 90 Ω, preferably at 77 Ω) (see, e.g., U.S.patent application Ser, No. 11/728,428; herein incorporated by referencein its entirety).

One significant source of undesired overheating of the device is thedielectric heating of the insulator (e.g., the coaxial insulator),potentially resulting in collateral tissue damage. The energy deliverydevices of the present invention are designed to prevent undesireddevice overheating. The energy delivery devices are not limited to aparticular manner of preventing undesired device heating. In someembodiments, the devices employ circulation of coolant. In someembodiments, the devices are configured to detect an undesired rise intemperature within the device (e.g., along the outer conductor) andautomatically or manually reduce such an undesired temperature risethrough flowing of coolant through the coolant passage channels.

In some embodiments, the energy delivery devices have improved coolingcharacteristics. For example, in some embodiments, the devices permitthe use of coolant without increasing the diameter of the device. Thisis in contrast to existing devices that flow coolant through an externalsleeve or otherwise increase the diameter of the device to accommodatethe flow of a coolant. In some embodiments, the energy delivery deviceshave therein one or more coolant passage channels for purposes ofreducing unwanted heat dissipation (see, e.g., U.S. patent applicationSer. No. 11/728,460; herein incorporated by reference in its entirety).In some embodiments, the energy delivery devices have therein a tube(e.g., needle, plastic tube, etc.) that runs the length of or partiallyruns the length of the device, designed to prevent device overheatingthrough circulation of coolant material. In some embodiments, channelsor tubes displace material from a dielectric component located betweenthe inner and outer conductors of a coaxial cable. In some embodiments,channels or tubes replace the dielectric material or substantiallyreplace the dielectric material. In some embodiments, channel or tubesdisplace a portion of the outer conductor. For example, in someembodiments, a portion of the outer conductor is removed or shaved offto generate a passageway for the flow of coolant. One such embodimentsis shown in FIG. 12. In this embodiment, a coaxial cable 900 has anouter conductor 910, an inner conductor 920, and a dielectric material930. In this embodiment, a region 940 of the outer conductor is removed,creating space for coolant flow. The only remaining outer conductormaterial the circumscribes or substantially circumscribes the coaxialcable is at distal 950 and proximal 960 end regions. A thin strip ofconductive material 970 connects the distal 950 and proximal 960 endregions. In this embodiments, a thin channel 980 is cut from theconductive material at the proximal end region 960 to permit coolantflow into the region where the outer conductive material was removed (orwas manufacture to be absent) 940. The present invention is not limitedby the size or shape of the passageway, so long as coolant can bedelivered. For example, in some embodiments, the passageway is a linearpath that runs the length of the coaxial cable. In some embodiments,spiral channels are employed. In some embodiments, the tube or channeldisplaces or replaces at least a portion of the inner conductor. Forexample, large portions of the inner conductor may be replaced with acoolant channel, leaving only small portions of metal near the proximaland distal ends of the device to permit tuning, wherein the portions areconnected by a thin strip of conducting material. In some embodiments, aregion of interior space is created within the inner or outer conductorto create one or more channels for coolant. For example, the innerconductor may be provided as a hollow tube of conductive material, witha coolant channel provided in the center. In such embodiments, the innerconductor can be used either for inflow or outflow (or both) of coolant.

In some embodiments, where a coolant tube is placed within the device,the tube has multiple channels for intake and outtake of coolant throughthe device. The device is not limited to a particular positioning of thetube (e.g., coolant needle) within the dielectric material. In someembodiments, the tube is positioned along the outside edge of thedielectric material, the middle of the dielectric material, or at anylocation within the dielectric material. In some embodiments, thedielectric material is pre-formed with a channel designed to receive andsecure the tube. In some embodiments, a handle is attached with thedevice, wherein the handle is configured to, for example, control thepassing of coolant into and out of the tube. In some embodiments, thetube is flexible. In some embodiments, the tube is inflexible. In someembodiments, the portions of the tube are flexible, while other portionsare inflexible. In some embodiments, the tube is compressible. In someembodiments, the tube is incompressible. In some embodiments, portionsof the tube are compressible, while other portions are incompressible.The tube is not limited to a particular shape or size. In someembodiments, wherein the tube is a coolant needle (e.g., a 29 gaugeneedle or equivalent size) that fits within a coaxial cable having adiameter equal or less than a 12 gauge needle. In some embodiments, theexterior of the tube has a coating of adhesive and/or grease so as tosecure the tube or permit sliding movement within the device. In someembodiments, the tube has one or more holes along its length that permitrelease of coolant into desired regions of the device. In someembodiments, the holes are initially blocked with a meltable material,such that a particular threshold of heat is required to melt thematerial and release coolant through the particular hole or holesaffected. As such, coolant is only released in areas that have reachedthe threshold heat level.

In some embodiments, coolant is preloaded into the antenna, handle orother component of the devices of the present invention. In otherembodiments, the coolant is added during use. In some pre-loadedembodiments, a liquid coolant is preloaded into, for example, the distalend of the antenna under conditions that create a self-perpetuatingvacuum. In some such embodiments, as the liquid coolant vaporizes, morefluid is drawn in by the vacuum.

The present invention is not limited by the nature of the coolantmaterial employed. Coolants included, but are not limited to, liquidsand gases. Exemplary coolant fluids include, but are not limited to, oneor more of or combinations of, water, glycol, air, inert gasses, carbondioxide, nitrogen, helium, sulfur hexafluoride, ionic solutions (e.g.,sodium chloride with or without potassium and other ions), dextrose inwater, Ringer's lactate, organic chemical solutions (e.g., ethyleneglycol, diethylene glycol, or propylene glycol), oils (e.g., mineraloils, silicone oils, fluorocarbon oils), liquid metals, freons,halomethanes, liquified propane, other haloalkanes, anhydrous ammonia,sulfur dioxide. In some embodiments, the coolant is a gas compressed ator near its critical point. In some embodiments, cooling occurs, atleast in part, by changing concentrations of coolant, pressure, orvolume. For example, cooling can be achieved via gas coolants using theJoule-Thompson effect. In some embodiments, the cooling is provided by achemical reaction. The devices are not limited to a particular type oftemperature reducing chemical reaction. In some embodiments, thetemperature reducing chemical reaction is an endothermic reaction. Thedevices are not limited to a particular manner of applying endothermicreactions for purposes of preventing undesired heating. In someembodiments, first and second chemicals are flowed into the device suchthat they react to reduce the temperature of the device. In someembodiments, the device is prepared with the first and second chemicalspreloaded in the device. In some embodiments, the chemicals areseparated by a barrier that is removed when desired. In someembodiments, the barrier is configured to melt upon exposure to apredetermined temperature or temperature range. In such embodiments, thedevice initiates the endothermical reaction only upon reaching a heatlevel that merits cooling. In some embodiments, multiple differentbarriers are located throughout the device such that local coolingoccurs only at those portions of the device where undesired heating isoccurring. In some embodiment, the barriers used are beads thatencompass one of the two chemicals. In some embodiments, the barriersare walls (e.g., discs in the shape of washers) that melt to combine thetwo chemicals. In some embodiments, the barriers are made of wax that isconfigured to melt at a predetermined temperature. The devices are notlimited to a particular type, kind or amount of meltable material. Insome embodiments, the meltable material is biocompatible. The devicesare not limited to a particular type, kind, or amount of first andsecond chemicals, so long as their mixture results in a temperaturereducing chemical reaction. In some embodiments, the first materialincludes barium hydroxide octahydrate crystals and the second materialis dry ammonium chloride. In some embodiments, the first material iswater and the second material is ammonium chloride. In some embodiments,the first material is thionyl chloride (SOCl₂) and the second materialis cobalt(II) sulfate heptahydrate. In some embodiments, the firstmaterial is water and the second material is ammonium nitrate. In someembodiments, the first material is water and the second material ispotassium chloride. In some embodiments, the first material is ethanoicacid and the second material is sodium carbonate. In some embodiments, ameltable material is used that, itself, reduces heat by melting anflowing in a manner such that the heat at the outer surface of thedevice is reduced.

In some embodiments, the energy delivery devices prevent undesiredheating and/or maintain desired energy delivery properties throughadjusting the amount of energy emitted from the device (e.g., adjustingthe energy wavelength resonating from the device) as temperaturesincrease. The devices are not limited to a particular method ofadjusting the amount of energy emitted from the device. In someembodiments, the devices are configured such that as the device reachesa certain threshold temperature or as the device heats over a range, theenergy wavelength resonating from the device is adjusted. The devicesare not limited to a particular method for adjusting energy wavelengthresonating from the device. In some embodiments, the device has thereina material that changes in volume as the temperature increases. Thechange in volume is used to move or adjust a component of the devicethat affects energy delivery. For example, in some embodiments, amaterial is used that expands with increasing temperature. The expansionis used to move the distal tip of the device outward (increasing itsdistance from the proximal end of the device), altering the energydelivery properties of the device. This finds particular use with thecenter-fed dipole embodiments of the present invention.

In certain embodiments, the present invention provides a devicecomprising an antenna configured for delivery of energy to a tissue,wherein a distal end of the antenna comprises a center-fed dipolecomponent comprising a rigid hollow tube encompassing a conductor,wherein a stylet is secured within the hollow tube (e.g., a titaniumstylet). In some embodiments, the hollow tube has a diameter equal to orless than a 20-gauge needle. In some embodiments, the hollow tube has adiameter equal to or less than a 17-gauge needle. In some embodiments,the hollow tube has a diameter equal to or less than a 12-gauge needle.In some embodiments, the device further comprises a tuning element foradjusting the amount of energy delivered to the tissue. In someembodiments, the device is configured to deliver a sufficient amount ofenergy to ablate the tissue or cause thrombosis. In some embodiments,the conductor extends halfway through the hollow tube. In someembodiments, the hollow tube has a length λ/2, wherein λ. is theelectromagnetic field wavelength in the medium of the tissue. In someembodiments, an expandable material is positioned near the stylet suchthat as the device increases in temperature the expandable materialexpands and pushes onto the stylet moving the stylet and changes theenergy delivery properties of the device. In some embodiments, theexpandable material is positioned behind (proximal to) a metal disc thatprovides the resonant element for the center-fed dipole device. As thematerial expands, the disc is pushed distally, adjusting the tuning ofthe device. The expandable material is preferably selected so that therate of expansion coincides with a desired change in energy delivery foroptimal results. However, it should be understood that any change in thedesired directions finds use with the invention. In some embodiments,the expandable material is wax.

In some embodiments, the device has a handle attached with the device,wherein the handle is configured to, for example, control the passing ofcoolant into and out of coolant channels. In some embodiments, only thehandle is cooled. In some embodiments, the handle is configured todeliver a gaseous coolant compressed at or near its critical point. Inother embodiments, the handle and an attached antenna are cooled. Insome embodiments, the handle automatically passes coolant into and outof the coolant channels after a certain amount of time and/or as thedevice reaches a certain threshold temperature. In some embodiments, thehandle automatically stops passage of coolant into and out of thecoolant channels after a certain amount of time and/or as thetemperature of the device drops below a certain threshold temperature.In some embodiments, coolant flowed through the handle is manuallycontrolled. In some embodiments, the handle has thereon one or more(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., display lights(e.g., LED lights)). In some embodiments, the lights are configured tofor identification purposes. For example, in some embodiments, thelights are used to differentiate between different probes (e.g.,activation of a first probe displays one light; a second probe twolights, a third probe three lights, or each probe has its own designatedlight, etc.). In some embodiments, the lights are used to identify theoccurrence of an event (e.g., the transmission of coolant through thedevice, the transmission of energy through the device, a movement of therespective probe, a change in a setting (e.g., temperature, positioning)within the device, etc.). The handles are not limited to a particularmanner of display (e.g., blinking, alternate colors, solid colors, etc).

In some embodiments, the energy delivery devices have therein a centerfed dipole component (see, e.g., U.S. patent application Ser. No.11/728,457; herein incorporated by reference in its entirety). In someembodiments, the energy delivery devices comprise a catheter withmultiple segments for transmitting and emitting energy (see, e.g., U.S.patent application Ser. No. 11/237,430, 11/237,136, and 11/236,985; eachherein incorporated by reference in their entireties). In someembodiments, the energy delivery devices comprise a triaxial microwaveprobe with optimized tuning capabilities to reduce reflective heat loss(see, e.g., U.S. Patent No. 7,101,369; see, also, U.S. patentapplication Ser. Nos. 10/834,802, 11/236,985, 11/237,136, 11,237,430,11/440,331, 11/452,637, 11/502,783, 11/514,628; and International PatentApplication No. PCT/US05/14534; herein incorporated by reference in itsentirety). In some embodiments, the energy delivery devices emit energythrough a coaxial transmission line (e.g., coaxial cable) having air orother gases as a dielectric core (see, e.g., U.S. patent applicationSer. No. 11/236,985; herein incorporated by reference in its entirety).In some such embodiments, materials that support the structure of thedevice between the inner and outer conductors may be removed prior touse. For example, in some embodiments, the materials are made of adissolvable or meltable material that is removed prior to or during use.In some embodiments, the materials are meltable and are removed duringuse (upon exposure to heat) so as to optimize the energy deliveryproperties of the device over time (e.g., in response to temperaturechanges in tissue, etc.).

The present invention is not limited to a particular coaxialtransmission line shape. Indeed, in some embodiments, the shape of thecoaxial transmission line and/or the dielectric element is adjustable tofit a particular need. In some embodiments, the cross-sectional shape ofthe coaxial transmission line and/or the dielectric element is circular.In some embodiments, the cross-sectional shape is non-circular (e.g.,oval, etc.). Such shapes may apply to the coaxial cable as a whole, ormay apply to one or more sub-components only. For example, an ovaldielectric material may be placed in a circular outer conductor. This,for example, has the advantage of creating two channels that may beemployed, for example, to circulate coolant. As another example,square/rectangular dielectric material may be placed in a circularconductor. This, for example, has the advantage of creating fourchannels. Different polygonal shapes in the cross-section (e.g.,pentagon, hexagon, etc.) may be employed to create different numbers andshapes of channels. The cross-sectional shape need not be the samethroughout the length of the cable. In some embodiments, a first shapeis used for a first region (e.g., a proximal region) of the cable and asecond shape is used for a second region (e.g., a distal region) of thecable. Irregular shapes may also be employed. For example, a dielectricmaterial having an indented groove running its length may be employed ina circular outer conductor to create a single channel of any desiredsize and shape. In some embodiments, the channel provides space forfeeding coolant, a needle, or other desired components into the devicewithout increasing the ultimate outer diameter of the device.

Likewise, in some embodiments, an antenna of the present invention has anon-circular cross-sectional shape along its length or for one or moresubsections of its length. In some embodiments, the antenna isnon-cylindrical, but contains a coaxial cable that is cylindrical. Inother embodiments, the antenna is non-cylindrical and contains a coaxialcable that is non-cylindrical (e.g., matching the shape of the antennaor having a different non-cylindrical shape). In some embodiments,having any one or more components (e.g., cannula, outer shell ofantenna, outer conductor of coaxial cable, dielectric material ofcoaxial cable, inner conductor of coaxial cable) possessing anon-cylindrical shape permits the creation of one or more channels inthe device that may be used, among other reasons, to circulate coolant.Non-circular shapes, particularly in the outer diameter of the antennaalso find use for certain medical or other applications. For example, ashape may be chosen to maximize flexibility or access to particularinner body locations. Shape may also be chosen to optimize energydelivery. Shape (e.g., non-cylindrical shape) may also be selected tomaximize rigidity and/or strength of the device, particularly for smalldiameter devices.

In certain embodiments, the present invention provides a devicecomprising an antenna, wherein the antenna comprises an outer conductorenveloped around an inner conductor, wherein the inner conductor isdesigned to receive and transmit energy, wherein the outer conductor hastherein at least one gap positioned circumferentially along the outerconductor, wherein multiple energy peaks are generated along the lengthof the antenna, the position of the energy peaks controlled by thelocation of the gap. In some embodiments, the energy is microwave energyand/or radiofrequency energy. In some embodiments, the outer conductorhas therein two of the gaps. In some embodiments, the antenna comprisesa dielectric layer disposed between the inner conductor and the outerconductor. In some embodiments, the dielectric layer has near-zeroconductivity. In some embodiments, the device further comprises astylet. In some embodiments, the inner conductor has a diameter ofapproximately 0.013 inches or less.

In some embodiments, any gaps or inconsistencies or irregularities inthe outer conductor or outer surface of the device are filled with amaterial to provide a smooth, even, or substantially smooth, even outersurface. In some embodiments, a heat-resistant, resin is used to fillgaps, inconsistencies, and/or irregularities. In some embodiments, theresin is biocompatible. In other embodiments, it is not biocompatible,but, for example, can be coated with a biocompatible material. In someembodiments, the resin is configurable to any desired size or shape. Assuch, the resin, when hardened, may be used to provide a sharp stylettip to the devices or any other desired physical shape.

In some embodiments, the device comprises a sharp stylet tip. The stylettip may be made of any material. In some embodiments, the tip is madefrom hardened resin. In some embodiments, the tip is metal. In someembodiments, the stylet tip is made from titanium or an equivalent oftitanium. In some embodiments, the stylet tip is braised to zirconia oran equivalent of zirconia. In some such embodiments, the metal tip is anextension of a metal portion of an antenna and is electrically active.

In some embodiments, the energy delivery devices are configured todeliver energy to a tissue region within a system comprising aprocessor, a power supply, a means of directing, controlling anddelivering power (e.g., a power splitter with the capability ofindividual control of power delivery to each antenna), an imagingsystem, a tuning system, and/or a temperature measurement adjustmentsystem.

The present invention is not limited to a particular type of processor.In some embodiments, the processor is designed to, for example, receiveinformation from components of the system (e.g., temperature monitoringsystem, energy delivery device, tissue impedance monitoring component,etc.), display such information to a user, and manipulate (e.g.,control) other components of the system. In some embodiments, theprocessor is configured to operate within a system comprising an energydelivery device, a power supply, a means of directing, controlling anddelivering power (e.g., a power splitter), an imaging system, a tuningsystem, and/or a temperature adjustment system.

The present invention is not limited to a particular type of powersupply. In some embodiments, the power supply is configured to provideany desired type of energy (e.g., microwave energy, radiofrequencyenergy, radiation, cryo energy, electroporation, high intensity focusedultrasound, and/or mixtures thereof). In some embodiments, the powersupply utilizes a power splitter to permit delivery of energy to two ormore energy delivery devices. In some embodiments, the power supply isconfigured to operate within a system comprising a power splitter, aprocessor, an energy delivery device, an imaging system, a tuningsystem, and/or a temperature adjustment system.

The present invention is not limited to a particular type of imagingsystem. In some embodiments, the imaging system utilizes imaging devices(e.g., endoscopic devices, stereotactic computer assisted neurosurgicalnavigation devices, thermal sensor positioning systems, motion ratesensors, steering wire systems, intraprocedural ultrasound, fluoroscopy,computerized tomography magnetic resonance imaging, nuclear medicineimaging devices triangulation imaging, interstitial ultrasound,microwave imaging, acoustic tomography, dual energy imaging,thermoacoustic imaging, infrared and/or laser imaging, electromagneticimaging) (see, e.g., U.S. Pat. Nos. 6,817,976, 6,577,903, and 5,697,949,5,603,697, and International Patent Application No. WO 06/005,579; eachherein incorporated by reference in their entireties). In someembodiments, the systems utilize endoscopic cameras, imaging components,and/or navigation systems that permit or assist in placement,positioning, and/or monitoring of any of the items used with the energysystems of the present invention. In some embodiments, the imagingsystem is configured to provide location information of particularcomponents of the energy delivery system (e.g., location of the energydelivery device). In some embodiments, the imaging system is configuredto operate within a system comprising a processor, an energy deliverydevice, a power supply, a tuning system, and/or a temperature adjustmentsystem. In some embodiments, the imaging system is located within theenergy delivery device. In some embodiments, the imaging system providesqualitative information about the ablation zone properties (e.g., thediameter, the length, the cross-sectional area, the volume). The imagingsystem is not limited to a particular technique for providingqualitative information. In some embodiments, techniques used to providequalitative information include, but are not limited to, time-domainreflectometry, time-of-flight pulse detection, frequency-modulateddistance detection, eigenmode or resonance frequency detection orreflection and transmission at any frequency, based on one interstitialdevice alone or in cooperation with other interstitial devices orexternal devices. In some embodiments, the interstitial device providesa signal and/or detection for imaging (e.g., electro-acoustic imaging,electromagnetic imaging, electrical impedance tomography).

The present invention is not limited to a particular tuning system. Insome embodiments, the tuning system is configured to permit adjustmentof variables (e.g., amount of energy delivered, frequency of energydelivered, energy delivered to one or more of a plurality of energydevices that are provided in the system, amount of or type of coolantprovided, etc.) within the energy delivery system. In some embodiments,the tuning system comprises a sensor that provides feedback to the useror to a processor that monitors the function of an energy deliverydevice continuously or at time points. The sensor may record and/orreport back any number of properties, including, but not limited to,heat (e.g., temperature) at one or more positions of a components of thesystem, heat at the tissue, property of the tissue, qualitativeinformation of the region, and the like. The sensor may be in the formof an imaging device such as CT, ultrasound, magnetic resonance imaging,fluoroscopy, nuclear medicine imaging, or any other imaging device. Insome embodiments, particularly for research application, the systemrecords and stores the information for use in future optimization of thesystem generally and/or for optimization of energy delivery underparticular conditions (e.g., patient type, tissue type, size and shapeof target region, location of target region, etc.). In some embodiments,the tuning system is configured to operate within a system comprising aprocessor, an energy delivery device, a power supply, an imaging, and/ora temperature adjustment system. In some embodiments, the imaging orother control components provide feedback to the ablation device so thatthe power output (or other control parameter) can be adjusted to providean optimum tissue response.

The present invention is not limited to a particular temperatureadjustment system. In some embodiments, the temperature adjustmentsystems are designed to reduce unwanted heat of various components ofthe system (e.g., energy delivery devices) during medical procedures(e.g., tissue ablation) or keep the target tissue within a certaintemperature range. In some embodiments, the temperature adjustmentsystems are configured to operate within a system comprising aprocessor, an energy delivery device, a power supply, a means ofdirecting, controlling and delivering power (e.g., a power splitter), atuning system, and/or an imaging system. In some embodiments, thetemperature adjustment system is designed to cool the energy deliverydevice to a temperature that is sufficient to temporarily adhere thedevice to internal patient tissue so as to prevent the energy devicefrom moving during a procedure (e.g., the ablation procedure).

In some embodiments, the systems further comprise temperature monitoringor reflected power monitoring systems for monitoring the temperature orreflected power of various components of the system (e.g., energydelivery devices) and/or a tissue region. In some embodiments, themonitoring systems are designed to alter (e.g., prevent, reduce) thedelivery of energy to a particular tissue region if, for example, thetemperature or amount of reflected energy, exceeds a predeterminedvalue. In some embodiments, the temperature monitoring systems aredesigned to alter (e.g., increase, reduce, sustain) the delivery ofenergy to a particular tissue region so as to maintain the tissue orenergy delivery device at a preferred temperature or within a preferredtemperature range.

In some embodiments, the systems further comprise an identification ortracking system configured, for example, to prevent the use ofpreviously used components (e.g., non-sterile energy delivery devices),to identify the nature of a component of the system so the othercomponents of the system may be appropriately adjusted for compatibilityor optimized function. In some embodiments, the system reads a bar codeor other information-conveying element associated with a component ofthe systems of the invention. In some embodiments, the connectionsbetween components of the system are altered (e.g., broken) followinguse so as to prevent additional uses. The present invention is notlimited by the type of components used in the systems or the usesemployed. Indeed, the devices may be configured in any desired mannerLikewise, the systems and devices may be used in any application whereenergy is to be delivered. Such uses include any and all medical,veterinary, and research applications. However, the systems and devicesof the present invention may be used in agricultural settings,manufacturing settings, mechanical settings, or any other applicationwhere energy is to be delivered.

In some embodiments, the systems are configured for percutaneous,intravascular, intracardiac, laparoscopic, or surgical delivery ofenergy. Likewise, in some embodiments, the systems are configured fordelivery of energy through a catheter, through a surgically developedopening, and/or through a body orifice (e.g., mouth, ear, nose, eyes,vagina, penis, anus) (e.g., a N.O.T.E.S. procedure). In someembodiments, the systems are configured for delivery of energy to atarget tissue or region. The present invention is not limited by thenature of the target tissue or region. Uses include, but are not limitedto, treatment of heart arrhythmia, tumor ablation (benign andmalignant), control of bleeding during surgery, after trauma, for anyother control of bleeding, removal of soft tissue, tissue resection andharvest, treatment of varicose veins, intraluminal tissue ablation(e.g., to treat esophageal pathologies such as Barrett's Esophagus andesophageal adenocarcinoma), treatment of bony tumors, normal bone, andbenign bony conditions, intraocular uses, uses in cosmetic surgery,treatment of pathologies of the central nervous system including braintumors and electrical disturbances, sterilization procedures (e.g.,ablation of the fallopian tubes) and cauterization of blood vessels ortissue for any purposes. In some embodiments, the surgical applicationcomprises ablation therapy (e.g., to achieve coagulative necrosis). Insome embodiments, the surgical application comprises tumor ablation totarget, for example, metastatic tumors. In some embodiments, the deviceis configured for movement and positioning, with minimal damage to thetissue or organism, at any desired location, including but not limitedto, the brain, neck, chest, abdomen, and pelvis. In some embodiments,the systems are configured for guided delivery, for example, bycomputerized tomography, ultrasound, magnetic resonance imaging,fluoroscopy, and the like.

In certain embodiments, the present invention provides methods oftreating a tissue region, comprising: providing a tissue region and asystem described herein (e.g., an energy delivery device, and at leastone of the following components: a processor, a power supply, a means ofdirecting, controlling and delivering power (e.g., a power splitter), atemperature monitor, an imager, a tuning system, and/or a temperaturereduction system); positioning a portion of the energy delivery devicein the vicinity of the tissue region, and delivering an amount of energywith the device to the tissue region. In some embodiments, the tissueregion is a tumor. In some embodiments, the delivering of the energyresults in, for example, the ablation of the tissue region and/orthrombosis of a blood vessel, and/or electroporation of a tissue region.In some embodiments, the tissue region is a tumor. In some embodiments,the tissue region comprises one or more of the heart, liver, genitalia,stomach, lung, large intestine, small intestine, brain, neck, bone,kidney, muscle, tendon, blood vessel, prostate, bladder, spinal cord,skin, veins, finger nails, and toe nails. In some embodiments, theprocessor receives information from sensors and monitors and controlsthe other components of the systems. In some embodiments, the energyoutput of the power supply is altered, as desired, for optimizedtherapy. In some embodiments, where more than one energy deliverycomponent is provided, the amount of energy delivered to each of thedelivery components is optimized to achieve the desired result. In someembodiments, the temperature of the system is monitored by a temperaturesensor and, upon reaching or approaching a threshold level, is reducedby activation of the temperature reduction system. In some embodimentsthe imaging system provides information to the processor, which isdisplayed to a user of the system and may be used in a feedback loop tocontrol the output of the system.

In some embodiments, energy is delivered to the tissue region indifferent intensities and from different locations within the device.For example, certain regions of the tissue region may be treated throughone portion of the device, while other regions of the tissue may betreated through a different portion of the device. In addition, two ormore regions of the device may simultaneously deliver energy to aparticular tissue region so as to achieve constructive phaseinterference (e.g., wherein the emitted energy achieves a synergisticeffect). In other embodiments, two or more regions of the device maydeliver energy so as to achieve a destructive interference effect. Insome embodiments, the method further provides additional devices forpurposes of achieving constructive phase interference and/or destructivephase interference. In some embodiments, phase interference (e.g.,constructive phase interference, destructive phase interference),between one or more devices, is controlled by a processor, a tuningelement, a user, and/or a power splitter.

The systems, devices, and methods of the present invention may be usedin conjunction with other systems, device, and methods. For example, thesystems, devices, and methods of the present invention may be used withother ablation devices, other medical devices, diagnostic methods andreagents, imaging methods and reagents, and therapeutic methods andagents. Use may be concurrent or may occur before or after anotherintervention. The present invention contemplates the use systems,devices, and methods of the present invention in conjunction with anyother medical interventions.

Additionally, integrated ablation and imaging systems are needed thatprovide feedback to a user and permit communication between varioussystem components. System parameters may be adjusted during the ablationto optimize energy delivery. In addition, the user is able to moreaccurately determine when the procedure is successfully completed,reducing the likelihood of unsuccessful treatments and/or treatmentrelated complications.

In certain embodiments, the present invention provides systems having,for example, a power source component that provides an energy source anda coolant source; a transport component for delivering energy andcoolant from the power source component to a control hub (e.g., controlpod); and a procedure device hub that receives energy and coolant fromthe transport component, the control hub positioned at a patientworkspace; the procedure device hub comprising a plurality of connectionports for attachment of one or more cables configured to deliver theenergy and/or the coolant to one or more energy delivery devices. Insome embodiments, the transport component is a low-loss cable. In someembodiments, the one or more cables configured to deliver energy to oneor more energy delivery devices is a flexible disposable cable. Theprocedure device hub is not limited to a particular weight. In someembodiments, the weight of the procedure device hub is such that it mayrest on a patient without causing harm and/or discomfort. In someembodiments, the procedure device hub weighs less than 10 pounds.

The system is not limited to use within a particular medical procedure.In some embodiments, the system is used within, for example, a CTscanning medical procedure, and/or an ultrasound imaging procedure.

The procedure device hub is not limited to a particular positionlocation during a medical procedure. Indeed, the procedure device hub isconfigured for positioning in a variety of arrangements. In someembodiments, the procedure device hub is configured for attachment ontoa procedure table (e.g., via the straps on a procedure table) (e.g.,through slots located on a procedure table). In some embodiments, theprocedure device hub is configured for attachment onto a patient's gown.In some embodiments, the procedure device hub is configured proceduredevice hub is configured for attachment onto a CT safety strap. In someembodiments, the procedure device hub is configured for attachment ontoa procedure table ring. In some embodiments, the procedure device hub isconfigured for attachment onto a sterile drape configured to placementonto a patient.

In some embodiments, the procedure device hub further comprises aprocedure device hub strap, wherein the procedure device hub strap isconfigured for attachment in a medical procedure location (e.g., aprocedure table, a patient's gown, a CT safety strap, a procedure tablering, a sterile drape, etc.).

The procedure device hub is not limited to delivering coolant to anenergy delivery device in a particular manner. In some embodiments, thecoolant delivered to the one or more energy delivery devices is a gasdelivered at a compressed pressure (e.g., the compressed pressure is ator near the critical point for the coolant). In some embodiments whereinthe coolant is a gas delivered at or near its critical point, thecoolant is CO₂.

In some embodiments, the power source is located outside of a sterilefield and the procedure device hub is located within a sterile field. Insome embodiments, the power source supplies microwave energy. In someembodiments, the power source supplies radio-frequency energy.

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the tubes configured to deliver coolant to the antenna,wherein the coolant is a gas compressed at or near its critical point.The devices are not limited to a particular gas. In some embodiments,the gas is CO₂. In some embodiments, the one or more coolant tubes orchannels are between an outer conductor and dielectric material of thecoaxial cable. In some embodiments, the one or more coolant tubes orchannels are between an inner conductor and dielectric material of thecoaxial cable. In some embodiments, the one or more coolant tubes orchannels are within an inner or outer conductor. In some embodiments,the device has therein a proximal region, a central region, and a distalregion. In some embodiments, the distal region is configured to deliverthe energy to the tissue. In some embodiments, the proximal and/orcentral regions have therein the coolant tubes or channels. In someembodiments, the distal portion does not have the coolant tubes orchannels.

In some embodiments, the device has therein one or more “stick” regionsconfigured to facilitate adherence of the tissue onto the stick region,for example, to stabilize the device in a desired position during energydelivery. In some embodiments, the stick region is configured to attainand maintain a temperature causing freezing of the tissue to the stickregion. In some embodiments, the stick region is positioned within thecentral region and/or the proximal region. The stick region is notlimited to any particular temperature for facilitating adherence of atissue region. In some embodiments, the stick region attains andmaintains a temperature for facilitating adherence of a tissue regionthrough contacting a region of the energy delivery device havingcirculated coolant. In some embodiments, the temperature of the stickregion is maintained at temperature low enough such that adherence of atissue region occurs upon contact with the stick region (e.g., such thata tissue region freezes onto the stick region). The stick region is notlimited to a particular material composition. In some embodiments, thestick region is, for example, a metal material, a ceramic material, aplastic material, and/or any combination of such substances. In someembodiments, the stick region is prevented from exposure to the distalregion of the device with a seal. In some embodiments, the seal ispositioned between the stick region and the distal region of the devicethereby preventing exposure of the stick region to the distal region. Insome embodiments, the seal is configured in an air/gas tight manner. Insome embodiments, the seal is a laser welding onto the device (e.g.,coaxial region). In some embodiments, the seal is induction soldered tothe device (e.g., coaxial region). In some embodiments, the seal ispartial (e.g., 60%/40%; 55%/45%; 50%/50%) laser welding and inductionsoldering.

In some embodiments, the distal region and the central region areseparated by a plug region designed to prevent cooling of the distalregion. The plug region is not limited to a particular manner ofpreventing cooling of the distal region. In some embodiments, the plugregion is designed to be in contact with a region having a reducedtemperature (e.g., the central region of the energy delivery devicehaving circulated coolant) without having its temperature reduced. Insome embodiments, the material of the plug region is such that it isable to be in contact with a material having a low temperature withouthaving its temperature substantially reduced (e.g., an insulatingmaterial). The plug region is not limited to a particular type ofinsulating material (e.g., a synthetic polymer (e.g., polystyrene,polyicynene, polyurethane, polyisocyanurate), aerogel, fibre-glass,cork).

In some embodiments, a device having a plug region permits simultaneousexposure of a tissue to a cooled region (e.g., the region of the deviceproximal to the plug region) and an uncooled region (e.g., the region ofthe device distal to the plug region).

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the coaxial cable having a dielectric region, thedielectric region having flexible and inflexible regions. In someembodiments, the flexible region is plastic, and the inflexible regionis ceramic. In some embodiments, the inflexible region is positioned atthe location of highest power emission.

In certain embodiments, the present invention provides devicescomprising an antenna configured for delivery of energy to a tissue, theantenna comprising one or more cooling tubes or channels within acoaxial cable, the device having therein one or more pullwires connectedto a pullwire anchor. In some embodiments, contraction of the one ormore pullwires connected to the pullwire anchor reduces flexibility ofthe device. In some embodiments, the one or more pullwires are designedto bend at particular temperatures (e.g., super elastic nitinol wires).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of an energy delivery system in anembodiment of the invention.

FIG. 2 shows various shapes of coaxial transmission lines and/or thedielectric elements in some embodiments of the present invention.

FIG. 3A and FIG. 3B display a coaxial transmission line embodimenthaving partitioned segments with first and second materials blocked bymeltable walls for purposes of preventing undesired device heating(e.g., heating along the outer conductor).

FIG. 4A and FIG. 4B display a coaxial transmission line embodimenthaving partitioned segments segregated by meltable walls containingfirst and second materials (e.g., materials configured to generate atemperature reducing chemical reaction upon mixing) preventing undesireddevice heating (e.g., heating along the outer conductor).

FIG. 5 shows a schematic drawing of a handle configured to control thepassing of coolant into and out of the coolant channels.

FIG. 6 shows a transverse cross-section schematic of coaxial cableembodiments having coolant passages.

FIG. 7 shows a coolant circulating tube (e.g., coolant needle, catheter)positioned within an energy emission device having an outer conductorand a dielectric material.

FIG. 8 schematically shows the distal end of a device (e.g., antenna ofan ablation device) of the present invention that comprises a center feddipole component of the present invention.

FIG. 9 shows the test setup and position of temperature measurementstations. As shown, the ablation needle shaft for all experiments was20.5 cm. Probes 1, 2 and 3 were located 4, 8 and 12 cm proximal to thetip of the stainless needle.

FIG. 10 shows treatment at 35% (microwaves “on” from 13:40 to 13:50)with anomalously high (6.5%) reflected power. Probe 3 was initiallyplaced just outside of the liver tissue, in air.

FIG. 11 shows 10 minute treatment at 45% (microwaves on from 14:58 to15:08) with anomalously high (6.5%) reflected power. Peak temperature atStation 4 was 40.25° C.

FIG. 12 shows one a coaxial cable having a region of its outer conductorremoved to create space for coolant flow in one embodiment of thepresent invention.

FIG. 13 shows a schematic view of an import/export box, a transportsheath, and a procedure device pod.

FIG. 14 shows an energy delivery device having two pullwires connectedwith a pullwire anchor.

FIG. 15 shows an external perspective of an energy delivery devicehaving inflexible regions and a flexible region.

FIG. 16 shows an energy delivery device having a narrow coaxialtransmission line connected with a larger coaxial transmission linepositioned within an antenna, which is connected with an innerconductor.

FIG. 17 shows a cross section of an energy delivery device havinginflexible regions and a flexible region.

FIG. 18 shows a procedure device hub connected to a procedure tablestrap.

FIG. 19 shows a custom sterile drape with a fenestration and a cableinserted through the fenestration.

FIG. 20 shows an energy delivery system of the present invention havinga generator connected to a procedure device hub via a cable, where theprocedure device hub is secured to a procedure table.

FIG. 21 demonstrates cooling with an energy delivery device. Atemperature profile during ablation measured 7 cm proximal to the tip ofthe antenna showed that cooling with chilled water can remove heatingcaused by more than 120 W input power (upper). A ˜3 cm ablation createdwith the cooled antenna (125 W, 5 min) shows no “tail” along theantenna. The ceramic tube and faceted tip make percutaneous introductionpossible (lower).

FIG. 22 shows a simulated temperature distribution along an antennashaft with various passive cooling techniques. A combination of thermalresistors and insulating sheath reduced proximal temperatures mostsignificantly.

FIG. 23 shows microwave (left) and RF (right) ablations created in 10min in normal porcine lung shown at equal scale. Microwave ablationswere larger and more spherical than RF ablations.

FIG. 24 shows the experimental setup (top) and results for temperaturesmeasured along an antenna shaft while 35 W of heat are generated insidethe antenna shaft (bottom). Only 1.0 stp L/min CO₂ flow was required tokeep temperatures from rising more than 8° C. at any point along theshaft. 10 stp L/min was able to offset 50 W of heating power.

FIG. 25 shows the experimental setup (top) and results for temperaturesmeasured along the antenna shaft while the antenna tip is maintained at150° C. for 0, 13 and 23.8 stp L/min NC-CO₂ flow (bottom). Note thatheating was only considered for thermal conduction from the antennatip—no internal heating was considered in this test.

FIG. 26 shows that pulses of CO₂ as small as 1 stp L/min for 10 scounterbalance the thermally conductive heating from the tip of theantenna.

FIG. 27 shows conventional and HighlY-contstrained backPRojection (HYPR)image resolution as a function of time

FIG. 28 shows standard and HighlY-contstrained backPRojection (HYPR)tumor images over periods of time.

FIG. 29 shows an energy delivery device embodiment.

FIG. 30 shows an energy delivery device embodiment.

FIG. 31 shows an energy delivery device embodiment within a proceduresetting.

FIG. 32A, FIG. 32B and FIG. 32C show examples of user interface softwarefor the energy delivery systems of the present invention.

FIG. 33 shows a triaxial microwave probe embodiment of the presentinvention.

DETAILED DESCRIPTION

The present invention relates to comprehensive systems, devices andmethods for delivering energy (e.g., microwave energy, radiofrequencyenergy) to tissue for a wide variety of applications, including medicalprocedures (e.g., tissue ablation, resection, cautery, vascularthrombosis, intraluminal ablation of a hollow viscus, cardiac ablationfor treatment of arrhythmias, electrosurgery, tissue harvest, cosmeticsurgery, intraocular use, etc.). In particular, the present inventionprovides systems for the delivery of microwave energy comprising a powersupply, a means of directing, controlling and delivering power (e.g., apower splitter), a processor, an energy emitting device, a coolingsystem, an imaging system, a temperature monitoring system, and/or atracking system. In certain embodiments, systems, devices, and methodsare provided for treating a tissue region (e.g., a tumor) through use ofthe energy delivery systems of the present invention.

The systems of the present invention may be combined within varioussystem/kit embodiments. For example, the present invention providessystems comprising one or more of a generator, a power distributionsystem, a means of directing, controlling and delivering power (e.g., apower splitter), an energy applicator, along with any one or moreaccessory component (e.g., surgical instruments, software for assistingin procedure, processors, temperature monitoring devices, etc.). Thepresent invention is not limited to any particular accessory component.

The systems of the present invention may be used in any medicalprocedure (e.g., percutaneous or surgical) involving delivery of energy(e.g., radiofrequency energy, microwave energy, laser, focusedultrasound, etc.) to a tissue region. The systems are not limited totreating a particular type or kind of tissue region (e.g., brain, liver,heart, blood vessels, foot, lung, bone, etc.). For example, the systemsof the present invention find use in ablating tumor regions. Additionaltreatments include, but are not limited to, treatment of heartarrhythmia, tumor ablation (benign and malignant), control of bleedingduring surgery, after trauma, for any other control of bleeding, removalof soft tissue, tissue resection and harvest, treatment of varicoseveins, intraluminal tissue ablation (e.g., to treat esophagealpathologies such as Barrett's Esophagus and esophageal adenocarcinoma),treatment of bony tumors, normal bone, and benign bony conditions,intraocular uses, uses in cosmetic surgery, treatment of pathologies ofthe central nervous system including brain tumors and electricaldisturbances, sterilization procedures (e.g., ablation of the fallopiantubes) and cauterization of blood vessels or tissue for any purposes. Insome embodiments, the surgical application comprises ablation therapy(e.g., to achieve coagulative necrosis). In some embodiments, thesurgical application comprises tumor ablation to target, for example,primary or metastatic tumors. In some embodiments, the surgicalapplication comprises the control of hemorrhage (e.g. electrocautery).In some embodiments, the surgical application comprises tissue cuttingor removal. In some embodiments, the device is configured for movementand positioning, with minimal damage to the tissue or organism, at anydesired location, including but not limited to, the brain, neck, chest,abdomen, pelvis, and extremities. In some embodiments, the device isconfigured for guided delivery, for example, by computerized tomography,ultrasound, magnetic resonance imaging, fluoroscopy, and the like.

The illustrated embodiments provided below describe the systems of thepresent invention in terms of medical applications (e.g., ablation oftissue through delivery of microwave energy). However, it should beappreciated that the systems of the present invention are not limited tomedical applications. The systems may be used in any setting requiringdelivery of energy to a load (e.g., agricultural settings, manufacturesettings, research settings, etc.). The illustrated embodiments describethe systems of the present invention in terms of microwave energy. Itshould be appreciated that the systems of the present invention are notlimited to a particular type of energy (e.g., radiofrequency energy,microwave energy, focused ultrasound energy, laser, plasma).

The systems of the present invention are not limited to any particularcomponent or number of components. In some embodiments, the systems ofthe present invention include, but are not limited to including, a powersupply, a means of directing, controlling and delivering power (e.g., apower splitter), a processor, an energy delivery device with an antenna,a cooling system, an imaging system, and/or a tracking system. Whenmultiple antennas are in use, the system may be used to individuallycontrol each antenna separately.

FIG. 1 shows an exemplary system of the invention. As shown, the energydelivery system comprises a power supply, a transmission line, a powerdistribution component (e.g., power splitter), a processor, an imagingsystem, a temperature monitoring system and an energy delivery device.In some embodiments, as shown, the components of the energy deliverysystems are connected via a transmission line, cables, etc. In someembodiments, the energy delivery device is separated from the powersupply, a means of directing, controlling and delivering power (e.g., apower splitter), processor, imaging system, temperature monitoringsystem across a sterile field barrier.

Exemplary components of the energy delivery systems are described inmore detail in the following sections: I. Power Supply; II. Energydelivery devices; III. Processor; IV. Imaging Systems; V. TuningSystems; VI. Temperature Adjustment Systems; VII. IdentificationSystems; VIII. Temperature Monitoring Devices; IX. Procedural DeviceHubs; and X. Uses for Energy Delivery Systems.

I. Power Supply

The energy utilized within the energy delivery systems of the presentinvention is supplied through a power supply. The present invention isnot limited to a particular type or kind of power supply. In someembodiments, the power supply is configured to provide energy to one ormore components of the energy delivery systems of the present invention(e.g., ablation devices). The power supply is not limited to providing aparticular type of energy (e.g., radiofrequency energy, microwaveenergy, radiation energy, laser, focused ultrasound, etc.). The powersupply is not limited to providing particular amounts of energy or at aparticular rate of delivery. In some embodiments, the power supply isconfigured to provide energy to an energy delivery device for purposesof tissue ablation.

The present invention is not limited to a particular type of powersupply. In some embodiments, the power supply is configured to provideany desired type of energy (e.g., microwave energy, radiofrequencyenergy, radiation, cryo energy, electroporation, high intensity focusedultrasound, and/or mixtures thereof). In some embodiments, the type ofenergy provided with the power supply is microwave energy. In someembodiments, the power supply provides microwave energy to ablationdevices for purposes of tissue ablation. The use of microwave energy inthe ablation of tissue has numerous advantages. For example, microwaveshave a broad field of power density (e.g., approximately 2 cmsurrounding an antenna depending on the wavelength of the appliedenergy) with a correspondingly large zone of active heating, therebyallowing uniform tissue ablation both within a targeted zone and inperivascular regions (see, e.g., International Publication No. WO2006/004585; herein incorporated by reference in its entirety). Inaddition, microwave energy has the ability to ablate large or multiplezones of tissue using multiple probes with more rapid tissue heating.Microwave energy has an ability to penetrate tissue to create deeplesions with less surface heating. Energy delivery times are shorterthan with radiofrequency energy and probes can heat tissue sufficientlyto create an even and symmetrical lesion of predictable and controllabledepth. Microwave energy is generally safe when used near vessels. Also,microwaves do not rely on electrical conduction as it radiates throughtissue, fluid/blood, as well as air. Therefore, microwave energy can beused in tissue, lumens, lungs, and intravascularly.

In some embodiments, the power supply comprises one or more energygenerators. In some embodiments, the generator is configured to provideas much as 100 watts of microwave power of a frequency of from 915 MHzto 5.8 GHz, although the present invention is not so limited. In someembodiments, a conventional magnetron of the type commonly used inmicrowave ovens is chosen as the generator. In some embodiments, asingle-magnetron based generator (e.g., with an ability to output 300Wthrough a single channel, or split into multiple channels) is utilized.It should be appreciated, however, that any other suitable microwavepower source can substituted in its place. In some embodiments, thetypes of generators include, but are not limited to, those availablefrom Cober-Muegge, LLC, Norwalk, Connecticut, USA, Sairem generators,and Gerling Applied Engineering generators. In some embodiments, thegenerator has at least approximately 60 Watts available (e.g., 50, 55,56, 57, 58, 59, 60, 61, 62, 65, 70, 100, 500, 1000 Watts). For ahigher-power operation, the generator is able to provide approximately300 Watts (e.g., 200 Watts, 280, 290, 300, 310, 320, 350, 400, 750Watts). In some embodiments, wherein multiple antennas are used, thegenerator is able to provide as much energy as necessary (e.g., 400Watts, 500, 750, 1000, 2000, 10,000 Watts). In some embodiments,multiple generators are used to provide energy (e.g., three 140 Wattamplifiers). In some embodiments, the generator comprises solid stateamplifier modules which can be operated separately and phase-controlled.In some embodiments, generator outputs are combined constructively toincrease total output power. In some embodiments, the power supplydistributes energy (e.g., collected from a generator) with a powerdistribution system. The present invention is not limited to aparticular power distribution system. In some embodiments, the powerdistribution system is configured to provide energy to an energydelivery device (e.g., a tissue ablation catheter) for purposes oftissue ablation. The power distribution system is not limited to aparticular manner of collecting energy from, for example, a generator.The power distribution system is not limited to a particular manner ofproviding energy to ablation devices. In some embodiments, the powerdistribution system is configured to transform the characteristicimpedance of the generator such that it matches the characteristicimpedance of an energy delivery device (e.g., a tissue ablationcatheter).

In some embodiments, the power distribution system is configured with avariable power splitter so as to provide varying energy levels todifferent regions of an energy delivery device or to different energydelivery devices (e.g., a tissue ablation catheter). In someembodiments, the power splitter is provided as a separate component ofthe system. In some embodiments, the power splitter is used to feedmultiple energy delivery devices with separate energy signals. In someembodiments, the power splitter electrically isolates the energydelivered to each energy delivery device so that, for example, if one ofthe devices experiences an increased load as a result of increasedtemperature deflection, the energy delivered to that unit is altered(e.g., reduced, stopped) while the energy delivered to alternate devicesis unchanged. The present invention is not limited to a particular typeor kind of power splitter. In some embodiments, the power splitter isdesigned by SM Electronics. In some embodiments, the power splitter isconfigured to receive energy from a power generator and provide energyto additional system components (e.g., energy delivery devices). In someembodiments the power splitter is able to connect with one or moreadditional system components (e.g., 1, 2, 3, 4, 5, 7, 10, 15, 20, 25,50, 100, 500 . . . ). In some embodiments, the power splitter isconfigured to deliver variable amounts of energy to different regionswithin an energy delivery device for purposes of delivering variableamounts of energy from different regions of the device. In someembodiments, the power splitter is used to provide variable amounts ofenergy to multiple energy delivery devices for purposes of treating atissue region. In some embodiments, the power splitter is configured tooperate within a system comprising a processor, an energy deliverydevice, a temperature adjustment system, a power splitter, a tuningsystem, and/or an imaging system. In some embodiments, the powersplitter is able to handle maximum generator outputs plus, for example,25% (e.g., 20%, 30%, 50%). In some embodiments, the power splitter is a1000-watt-rated 2-4 channel power splitter.

In some embodiments, where multiple antennas are employed, the system ofthe present invention may be configured to run them simultaneously orsequentially (e.g., with switching). In some embodiments, the system isconfigured to phase the fields for constructive or destructiveinterference. Phasing may also be applied to different elements within asingle antenna. In some embodiments, switching is combined with phasingsuch that multiple antennas are simultaneously active, phase controlled,and then switched to a new set of antennas (e.g., switching does notneed to be fully sequential). In some embodiments, phase control isachieved precisely. In some embodiments, phase is adjusted continuouslyso as to move the areas of constructive or destructive interference inspace and time. In some embodiments, the phase is adjusted randomly. Insome embodiments, random phase adjustment is performed by mechanicaland/or magnetic interference.

II. Energy Delivery Devices

The energy delivery systems of the present invention contemplate the useof any type of device configured to deliver (e.g., emit) energy (e.g.,ablation device, surgical device, etc.) (see, e.g., U.S. Pat. Nos.7,101,369, 7,033,352, 6,893,436, 6,878,147, 6,823,218, 6,817,999,6,635,055, 6,471,696, 6,383,182, 6,312,427, 6,287,302, 6,277,113,6,251,128, 6,245,062, 6,026,331, 6,016,811, 5,810,803, 5,800,494,5,788,692, 5,405,346, 4,494,539, U.S. patent application Ser. Nos.11/728,460, 11/728,457, 11/728,428, 11/237,136, 11/236,985, 10/980,699,10/961,994, 10/961,761, 10/834,802, 10/370,179, 09/847,181; GreatBritain Patent Application Nos. 2,406,521, 2,388,039; European PatentNo. 1395190; and International Patent Application Nos. WO 06/008481, WO06/002943, WO 05/034783, WO 04/112628, WO 04/033039, WO 04/026122, WO03/088858, WO 03/039385 WO 95/04385; each herein incorporated byreference in their entireties). Such devices include any and allmedical, veterinary, and research applications devices configured forenergy emission, as well as devices used in agricultural settings,manufacturing settings, mechanical settings, or any other applicationwhere energy is to be delivered.

In some embodiments, the systems utilize energy delivery devices havingtherein antennae configured to emit energy (e.g., microwave energy,radiofrequency energy, radiation energy). The systems are not limited toparticular types or designs of antennae (e.g., ablation device, surgicaldevice, etc.). In some embodiments, the systems utilize energy deliverydevices having linearly shaped antennae (see, e.g., U.S. Pat. Nos.6,878,147, 4,494,539, U.S. patent application Ser. Nos. 11/728,460,11/728,457, 11/728,428, 10/961,994, 10/961,761; and International PatentApplication No., WO 03/039385; each herein incorporated by reference intheir entireties). In some embodiments, the systems utilize energydelivery devices having non-linearly shaped antennae (see, e.g., U.S.Pat. Nos. 6,251,128, 6,016,811, and 5,800,494, U.S. patent applicationSer. No. 09/847,181, and International Patent Application No. WO03/088858; each herein incorporated by reference in their entireties).In some embodiments, the antennae have horn reflection components (see,e.g., U.S. Pat. Nos. 6,527,768, 6,287,302; each herein incorporated byreference in their entireties). In some embodiments, the antenna has adirectional reflection shield (see, e.g., U.S. Pat. No. 6,312,427;herein incorporated by reference in its entirety). In some embodiments,the antenna has therein a securing component so as to secure the energydelivery device within a particular tissue region (see, e.g., U.S. Pat.Nos. 6,364,876, and 5,741,249; each herein incorporated by reference intheir entireties).

Generally, antennae configured to emit energy comprise coaxialtransmission lines. The devices are not limited to particularconfigurations of coaxial transmission lines. Examples of coaxialtransmission lines include, but are not limited to, coaxial transmissionlines developed by Pasternack, Micro-coax, and SRC Cables. In someembodiments, the coaxial transmission line has a center conductor, adielectric element, and an outer conductor (e.g., outer shield). In someembodiments, the systems utilize antennae having flexible coaxialtransmission lines (e.g., for purposes of positioning around, forexample, pulmonary veins or through tubular structures) (see, e.g., U.S.Pat. Nos. 7,033,352, 6,893,436, 6,817,999, 6,251,128, 5,810,803,5,800,494; each herein incorporated by reference in their entireties).In some embodiments, the systems utilize antennae having rigid coaxialtransmission lines (see, e.g., U.S. Pat. No. 6,878,147, U.S. patentapplication Ser. Nos. 10/961,994, 10/961,761, and International PatentApplication No. WO 03/039385; each herein incorporated by reference intheir entireties).

In some embodiments, the energy delivery devices have a coaxialtransmission line positioned within the antenna, and a coaxialtransmission line connecting with the antenna. In some embodiments, thesize of the coaxial transmission line within the antenna is larger thanthe coaxial transmission line connected with the antenna. The coaxialtransmission line within the antenna and the coaxial transmission lineconnecting with the antenna are not limited to particular sizes. Forexample, in some embodiments, whereas the coaxial transmission lineconnected with the antenna is approximately 0.032 inches, the size ofthe coaxial transmission line within the antenna is larger than 0.032inches (e.g., 0.05 inches, 0.075 inches, 0.1 inches, 0.5 inches). Insome embodiments, the coaxial transmission line within the antenna hasan inner conductor that is stiff and thick. In some embodiments, the endof the coaxial transmission line within the antenna is sharpened forpercutaneous use. In some embodiments, the dielectric coating of thecoaxial transmission line within the antenna is PTFE (e.g., for purposesof smoothing transitions from a cannula to an inner conductor (e.g., athin and sharp inner conductor)). FIG. 16 shows an energy deliverydevice 1600 having a narrow coaxial transmission line 1610 connectedwith a larger coaxial transmission line 1620 positioned within anantenna 1630, which is connected with an inner conductor 1640.

The present invention is not limited to a particular coaxialtransmission line shape. Indeed, in some embodiments, the shape of thecoaxial transmission line and/or the dielectric element is selectedand/or adjustable to fit a particular need. FIG. 2 shows some of thevarious, non-limiting shapes the coaxial transmission line and/or thedielectric element may assume.

In some embodiments, the outer conductor is a 20-gauge needle or acomponent of similar diameter to a 20-gauge needle. Preferably, forpercutaneous use, the outer conductor is not larger than a 17-gaugeneedle (e.g., no larger than a 16-gauge needle). In some embodiments,the outer conductor is a 17-gauge needle. However, in some embodiments,larger devices are used, as desired. For example, in some embodiments, a12-gauge diameter is used. The present invention is not limited by thesize of the outer conductor. In some embodiments, the outer conductor isconfigured to fit within series of larger needles for purposes ofassisting in medical procedures (e.g., assisting in tissue biopsy) (see,e.g., U.S. Pat. Nos. 6,652,520, 6,582,486, 6,355,033, 6,306,132; eachherein incorporated by reference in their entireties). In someembodiments, the center conductor is configured to extend beyond theouter conductor for purposes of delivering energy to a desired location.In some embodiments, some or all of the feedline characteristicimpedance is optimized for minimum power dissipation, irrespective ofthe type of antenna that terminates at its distal end.

In some embodiments, the energy delivery devices are provided with aproximal portion and a distal portion, wherein the distal portion isdetachable and provided in a variety of different configurations thatcan attach to a core proximal portion. For example, in some embodiments,the proximal portion comprises a handle and an interface to othercomponents of the system (e.g., power supply) and the distal portioncomprises a detachable antenna having desired properties. A plurality ofdifferent antenna configured for different uses may be provided andattached to the handle unit for the appropriate indication.

In some embodiments, multiple (e.g., more than 1) (e.g., 2, 3, 4, 5, 10,20, etc.) coaxial transmission lines and/or triaxial transmission linesare positioned within each energy delivery device for purposes ofdelivering high amounts of energy over an extended period of time. Inexperiments conducted during the course of developing embodiments forthe present invention, it was determined that an energy delivery devicehaving three lower power coaxial transmission lines (e.g., positionedwithin the same probe) (e.g., within a 13 gauge needle) was able todeliver higher amounts of energy for a longer period of time than anenergy delivery device having a higher power coaxial transmission line.

In some embodiments, the energy delivery devices comprise a triaxialmicrowave probe with optimized tuning capabilities (see, e.g., U.S. Pat.No. 7,101,369; see, also, U.S. patent application Ser. Nos. 10/834,802,11/236,985, 11/237,136, 11,237,430, 11/440,331, 11/452,637, 11/502,783,11/514,628; and International Patent Application No. PCT/US05/14534;herein incorporated by reference in its entirety). The triaxialmicrowave probes are not limited to particular optimized tuningcapabilities. In some embodiments, the triaxial microwave probes havepre-defined optimized tuning capabilities specific for a particulartissue type. FIG. 33 shows a triaxial microwave probe 33000 having afirst conductor 33100, a second conductor 33200 coaxially around thefirst conductor 33100 but insulated therefrom, and a tubular thirdconductor 33300 coaxially around the first conductor 33100 and thesecond conductor 33200. In some embodiments, the first conductor 33100is configured to extend beyond the second conductor 33200 into tissue,for example, when a distal end of triaxial microwave probe 33000 isinserted into a body for microwave ablation. As shown in FIG. 33, thedistance the first conductor 33100 is extended from the second conductor33200 is the active length 33400. In some embodiments, the secondconductor 33200 is configured to extend beyond the third conductor 33300into tissue. As shown in FIG. 33, the distance the second conductor33200 is extended from the third conductor 33300 is the insertion depth33500. In experiments conducted during the course of developingembodiments for the present invention, optimal insertion depth andactive length measurements for specific tissue types were determined.For example, using a triaxial microwave probe as shown in FIG. 33 withlung tissue, the optimal insertion depth was 3.6 mm and the optimalactive length was 16 mm. For example, using a triaxial microwave probeas shown in FIG. 33 with liver tissue, the optimal insertion depth was3.6 mm and the optimal active length was 15 mm. For example, using atriaxial microwave probe as shown in FIG. 33 with kidney tissue, theoptimal insertion depth was 3.6 mm and the optimal active length was 15mm. In some embodiments, triaxial microwave probes are configured toablate a smaller tissue region (e.g., ablating only the edge of anorgan, ablating a small tumor, etc.). In such embodiments, the length ofthe first conductor is decreased (e.g., such that the wire contacts thetip of the so as to retain a small ablation region).

In some embodiments, the devices of the present invention are configuredto attach with a detachable handle. The present invention is not limitedto a particular type of detachable handle. In some embodiments, thedetachable handle is configured to connect with multiple devices (e.g.,1, 2, 3, 4, 5, 10, 20, 50 . . . ) for purposes of controlling the energydelivery through such devices. In some embodiments, the handle isdesigned with a power amplifier for providing power to an energydelivery device.

In some embodiments, the device is designed to physically surround aparticular tissue region for purposes of energy delivery (e.g., thedevice may be flexibly shaped around a particular tissue region). Forexample, in some embodiments, the device may be flexibly shaped around ablood vessel (e.g., pulmonary vein) for purposes of delivering energy toa precise region within the tissue.

In some embodiments, the energy delivery devices are configured forshape retention upon exposure to a compressive force. The energydelivery devices are not limited to a particular configuration forretaining shape upon exposure to a compressive force. In someembodiments, the energy delivery devices have therein a pullwire systemfor purposes of shape retention upon compression. The present inventionis not limited to a particular type of pullwire system. In someembodiments, the pullwire system comprises one or more pullwires (e.g.,1 pullwire, 2 pullwires, 5 pullwires, 10 pullwires, 50 pullwires)connected with a pullwire anchor. In some embodiments, contraction(e.g., pushing, pulling) of the one or more pullwires connected to thepullwire anchor (e.g., contraction by a user) results in the assumptionof an inflexible state by the energy delivery device such that uponexposure to a compressive force the energy delivery device retains itsshape. In some embodiments, the pullwires can be locked in a contractedposition. In some embodiments, the energy delivery devices having one ormore pullwires connected with a pullwire anchor retains flexibility inthe absence pullwire contraction. FIG. 14 shows an energy deliverydevice 1400 having two pullwires 1410, 1420 connected with a pullwireanchor 1430. In some embodiments, the energy delivery devices have threeor more pullwires arranged in a symmetrical pattern which arepre-stressed thereby providing a constant inflexible shape. In someembodiments, the pullwires are configured to automatically contract inresponse to a stimulation (e.g., an electrical stimulation, acompressive stimulation) (e.g., muscle wires). In some embodiments, thepullwires are configured to provide a balancing force in response to acompressive force (e.g., a counteracting force). In some embodiments,the pullwires are designed to bend at particular temperatures (e.g.,super elastic nitinol wires). In some embodiments, the bending ofpullwires at particular temperatures is a detectable event that can beused to monitor the status of a procedure.

In some embodiments, the energy delivery devices are configured to haveboth flexible and inflexible regions. The energy delivery devices arenot limited to particular configurations for having both flexible andinflexible regions. In some embodiments, the flexible regions compriseplastic (e.g., PEEK). In some embodiments, the inflexible regionscomprise ceramic. The flexible and inflexible regions are not limited toparticular positions within the energy delivery devices. In someembodiments, the flexible region is positioned in a region experiencinglower amounts of microwave field emission. In some embodiments, theinflexible region is positioned in a region experiencing high amounts ofmicrowave field emission (e.g., located over the proximal portion of theantenna to provide dielectric strength and mechanical rigidity). FIG. 15shows an external perspective of an energy delivery device 1500 havinginflexible regions 1510 and 1520 (e.g., ceramic), and a flexible region1530 (e.g., PEEK). FIG. 17 shows a cross section of an energy deliverydevice 1700 having inflexible regions 1710 and 1720, and a flexibleregion 1730. As shown, the inflexible regions 1710 and 1720 aregradually tapered so as to, for example, provide a larger surface areafor bonding with the cannula, and so as to, for example, distributestresses from bending forces over a larger surface area. As shown, theflexible region 1730 is positioned on the outside of the joint forpurposes of improving strength due to its large diameter size. In someembodiments, the gradual taper of the inflexible regions are filled witha bonding material to provide additional strength. In some embodiments,the energy delivery devices have a heat shrink over the distal portion(e.g., the antenna) for providing additional durability.

In some embodiments, the material of the antenna is durable and providesa high dielectric constant. In some embodiments, the material of theantenna is zirconium and/or a functional equivalent of zirconium. Insome embodiments, the energy delivery device is provided as two or moreseparate antenna attached to the same or different power supplies. Insome embodiments, the different antenna are attached to the same handle,while in other embodiments different handles are provided for eachantenna. In some embodiments, multiple antennae are used within apatient simultaneously or in series (e.g., switching) to deliver energyof a desired intensity and geometry within the patient. In someembodiments, the antennas are individually controllable. In someembodiments, the multiple antennas may be operated by a single user, bya computer, or by multiple users.

In some embodiments, the energy delivery devices are designed to operatewithin a sterile field. The present invention is not limited to aparticular sterile field setting. In some embodiments, the sterile fieldincludes a region surrounding a subject (e.g., an operating table). Insome embodiments, the sterile field includes any region permittingaccess only to sterilized items (e.g., sterilized devices, sterilizedaccessory agents, sterilized body parts). In some embodiments, thesterile field includes any region vulnerable to pathogen infection. Insome embodiments, the sterile field has therein a sterile field barrierestablishing a barrier between a sterile field and a non-sterile field.The present invention is not limited to a particular sterile fieldbarrier. In some embodiments, the sterile field barrier is the drapessurrounding a subject undergoing a procedure involving the systems ofthe present invention (e.g., tissue ablation). In some embodiments, aroom is sterile and provides the sterile field. In some embodiments, thesterile field barrier is established by a user of the systems of thepresent invention (e.g., a physician). In some embodiments, the sterilefield barrier hinders entry of non-sterile items into the sterile field.In some embodiments, the energy delivery device is provided in thesterile field, while one or more other components of the system (e.g.,the power supply) are not contained in the sterile field.

In some embodiments, the energy delivery devices have therein protectionsensors designed to prevent undesired use of the energy deliverydevices. The energy delivery devices are not limited to a particulartype or kind of protection sensors. In some embodiments, the energydelivery devices have therein a temperature sensor designed to measurethe temperature of, for example, the energy delivery device and/or thetissue contacting the energy delivery device. In some embodiments, as atemperature reaches a certain level the sensor communicates a warning toa user via, for example, the processor. In some embodiments, the energydelivery devices have therein a skin contact sensor designed to detectcontact of the energy delivery device with skin (e.g., an exteriorsurface of the skin). In some embodiments, upon contact with undesiredskin, the skin contact sensor communicates a warning to a user via, forexample, the processor. In some embodiments, the energy delivery deviceshave therein an air contact sensor designed to detect contact of theenergy delivery device with ambient air (e.g., detection throughmeasurement of reflective power of electricity passing through thedevice). In some embodiments, upon contact with undesired air, the skincontact sensor communicates a warning to a user via, for example, theprocessor. In some embodiments, the sensors are designed to prevent useof the energy delivery device (e.g., by automatically reducing orpreventing power delivery) upon detection of an undesired occurrence(e.g., contact with skin, contact with air, undesired temperatureincrease/decrease). In some embodiments, the sensors communicate withthe processor such that the processor displays a notification (e.g., agreen light) in the absence of an undesired occurrence. In someembodiments, the sensors communicate with the processor such that theprocessor displays a notification (e.g., a red light) in the presence ofan undesired occurrence and identifies the undesired occurrence.

In some embodiments, the energy delivery devices are used above amanufacturer's recommended power rating. In some embodiments, coolingtechniques described herein are applied to permit higher power delivery.The present invention is not limited to a particular amount of powerincrease. In some embodiments, power ratings exceed manufacturer'srecommendation by 5× or more (e.g., 5×, 6×, 10×, 15×, 20×, etc.).

In addition, the devices of the present invention are configured todeliver energy from different regions of the device (e.g., outerconductor segment gaps, described in more detail below) at differenttimes (e.g., controlled by a user) and at different energy intensities(e.g., controlled by a user). Such control over the device permits thephasing of energy delivery fields for purposes of achieving constructivephase interference at a particular tissue region or destructive phaseinterference at a particular tissue region. For example, a user mayemploy energy delivery through two (or more) closely positioned outerconductor segments so as to achieve a combined energy intensity (e.g.,constructive phase interference). Such a combined energy intensity maybe useful in particularly deep or dense tissue regions. In addition,such a combined energy intensity may be achieved through utilization oftwo (or more) devices. In some embodiments, phase interference (e.g.,constructive phase interference, destructive phase interference),between one or more devices, is controlled by a processor, a tuningelement, a user, and/or a power splitter. Thus, the user is able tocontrol the release of energy through different regions of the deviceand control the amount of energy delivered through each region of thedevice for purposes of precisely sculpting an ablation zone.

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices with optimized characteristicimpedance, energy delivery devices having cooling passage channels,energy delivery devices with a center fed dipole, and energy deliverydevices having a linear array of antennae components (each described inmore detail above and below).

As described in the Summary of the Invention, above, the presentinvention provides a wide variety of methods for cooling the devices.Some embodiments employ meltable barriers that, upon melting, permit thecontact of chemicals that carry out an endothermic reaction. An exampleof such an embodiment is shown in FIG. 3. FIGS. 3A and 3B display aregion of a coaxial transmission line (e.g., a channel) havingpartitioned segments with first and second materials blocked by meltablewalls for purposes of preventing undesired device heating (e.g., heatingalong the outer conductor). FIGS. 3A and 3B depict a standard coaxialtransmission line 300 configured for use within any of the energydelivery devices of the present invention. As shown in FIG. 3A, thecoaxial transmission line 300 has a center conductor 310, a dielectricmaterial 320, and an outer conductor 330. In addition, the coaxialtransmission line 300 has therein four partitioned segments 340segregated by walls 350 (e.g., meltable wax walls). The partitionedsegments 340 are divided into first partitioned segments 360 and secondpartitioned segments 370. In some embodiments, as shown in FIG. 3A, thefirst partitioned segments 360 and second partitioned segments 370 aresuccessively staggered. As shown in FIG. 3A, the first partitionedsegments 360 contain a first material (shading type one) and the secondpartitioned segments 370 contain a second material (shading type two).The walls 350 prevent the first material and second material frommixing. FIG. 3B shows the coaxial transmission line 300 described inFIG. 3A following an event (e.g., a temperature increase at one of thepartitioned segments 340). As shown, one of the walls 350 has meltedthereby permitting mixing of the first material contained in a region360 and second material contained in a region 370. FIG. 3B further showsnon-melted walls 350 where the temperature increase did not rise above acertain temperature threshold.

FIG. 4 shows an alternative embodiment. FIGS. 4A and 4B display acoaxial transmission line embodiment having partitioned segmentssegregated by meltable walls containing first and second materials(e.g., materials configured to generate a temperature reducing chemicalreaction upon mixing) preventing undesired device heating (e.g., heatingalong the outer conductor). FIGS. 4A and 4B show a coaxial transmissionline 400 configured for use within any of the energy delivery devices ofthe present invention. As shown in FIG. 4A, the coaxial transmissionline 400 has a center conductor 410, a dielectric material 420, and anouter conductor 430. In addition, the coaxial transmission line 400 hastherein four partitioned segments 440 segregated by walls 450. The walls450 each contain a first material 460 separated from a second material470. FIG. 4B shows the coaxial transmission line 400 described in FIG.4A following an event (e.g., a temperature increase at one of thepartitioned segments 440). As shown, one of the walls 450 has meltedthereby permitting mixing of the first material 460 and second material470 within the adjacent partitioned segments 440. FIG. 4B furtherdemonstrates non-melted walls 450 where the temperature increase did notrise above a certain temperature threshold.

In some embodiments, the device further comprises an anchoring elementfor securing the antenna at a particular tissue region. The device isnot limited to a particular type of anchoring element. In someembodiments, the anchoring element is an inflatable balloon (e.g.,wherein inflation of the balloon secures the antenna at a particulartissue region). An additional advantage of utilizing an inflatableballoon as an anchoring element is the inhibition of blood flow or airflow to a particular region upon inflation of the balloon. Such air orblood flow inhibition is particularly useful in, for example, cardiacablation procedures and ablation procedures involving lung tissue,vascular tissue, and gastrointestinal tissue. In some embodiments, theanchoring element is an extension of the antenna designed to engage(e.g., latch onto) a particular tissue region. Further examples include,but are not limited to, the anchoring elements described in U.S. Pat.Nos. 6,364,876, and 5,741,249; each herein incorporated by reference intheir entireties. In some embodiments, the anchoring element has acirculating agent (e.g. a gas delivered at or near its critical point;CO₂) that freezes the interface between antenna and tissue therebysticking the antenna in place. In such embodiments, as the tissue meltsthe antenna remains secured to the tissue region due to tissuedesiccation.

Thus, in some embodiments, the devices of the present invention are usedin the ablation of a tissue region having high amounts of air and/orblood flow (e.g., lung tissue, cardiac tissue, gastrointestinal tissue,vascular tissue). In some embodiments involving ablation of tissueregions having high amounts of air and/or blood flow, an element isfurther utilized for inhibiting the air and/or blood flow to that tissueregion. The present invention is not limited to a particular air and/orblood flow inhibition element. In some embodiments, the device iscombined with an endotracheal/endobronchial tube. In some embodiments, aballoon attached with the device may be inflated at the tissue regionfor purposes of securing the device(s) within the desired tissue region,and inhibiting blood and/or air flow to the desired tissue region.

Thus, in some embodiments, the systems, devices, and methods of thepresent invention provide an ablation device coupled with a componentthat provides occlusion of a passageway (e.g., bronchial occlusion). Theocclusion component (e.g., inflatable balloon) may be directly mountedon the ablation system or may be used in combination with anothercomponent (e.g., an endotracheal or endobronchial tube) associated withthe system. In some embodiments, the devices of the present inventionmay be mounted onto additional medical procedure devices. For example,the devices may be mounted onto endoscopes, intravascular catheters, orlaproscopes. In some embodiments, the devices are mounted onto steerablecatheters. In some embodiments, a flexible catheter is mounted on anendoscope, intravascular catheter or laparoscope. For example, theflexible catheter, in some embodiments, has multiple joints (e.g., likea centipede) that permits bending and steering as desired to navigate tothe desired location for treatment.

In some embodiments, the energy delivery devices have therein a plugregion designed to separate interior portion of the energy deliverydevice so as to, for example, prevent cooling or heating of a portion orportions of the device while permitting cooling or heating of otherportions. The plug region may be configured to segregate any desiredregion or regions of an energy delivery device from any other. In someembodiments, the plug region is designed to prevent cooling of one ormore regions of an energy delivery device. In some embodiments, the plugregion is designed to prevent cooling of the portion of the energydelivery device configured to deliver ablative energy. The plug regionis not limited to a particular manner of preventing cooling of a portionof the device. In some embodiments, the plug region is designed to be incontact with a region having a reduced temperature (e.g., a region ofthe energy delivery device having circulated coolant). In someembodiments, the material of the plug region is such that it is able tobe in contact with a material or region having a low temperature withouthaving its temperature significantly reduced (e.g., an insulatingmaterial). The plug region is not limited to a particular type ofinsulating material (e.g., a synthetic polymer (e.g., polystyrene,polyicynene, polyurethane, polyisocyanurate), aerogel, fibre-glass,cork). The plug region is not limited to particular size dimensions. Insome embodiments, the size of the plug region is such that it is able toprevent the cooling effect of a circulating coolant from reducing thetemperature of other regions of the energy delivery device. In someembodiments, the plug region is positioned along the entire cannulaportion of an energy delivery device. In some embodiments, the plugregion is positioned at a distal portion of the cannula portion of anenergy delivery device. In some embodiments, the plug region wrapsaround the external portion of the cannula portion of an energy deliverydevice.

In some embodiments, the energy delivery devices have therein a “stick”region designed for securing the energy delivery device to a tissueregion. The stick region is not limited to a particular manner offacilitating association of an energy delivery device to a tissueregion. In some embodiments, the stick region is configured to attainand maintain a reduced temperature such that upon contact with a tissueregion, the tissue region adheres to the stick region thereby resultingin attachment of the energy delivery device with the tissue region. Thestick region is not limited to a particular material composition. Insome embodiments, the stick region is, for example, a metal material, aceramic material, a plastic material, and/or any combination of suchsubstances. In some embodiments, the stick region comprises any kind ofmaterial able to attain and maintain a temperature such that uponcontact with a tissue region induces adherence of the tissue region ontothe stick region. The stick region is not limited to particular sizedimensions. In some embodiments, the size of the stick region is suchthat it is able to maintain adherence of a tissue region duringsimultaneous tissue ablation and/or simultaneous movement (e.g.,positioning) of the energy delivery device. In some embodiments, two ormore stick regions are provided. In some embodiments, the stick regionis prevented from exposure to the distal region of the device with aseal. In some embodiments, the seal is positioned between the stickregion and the distal region of the device thereby preventing exposureof the stick region to the distal region. In some embodiments, the sealis configured in an air/gas tight manner. In some embodiments, the sealis a laser welding onto the device (e.g., coaxial region). In someembodiments, the seal is induction soldered to the device (e.g., coaxialregion). In some embodiments, the seal is partial (e.g., 60%/40%;55%/45%; 50%/50%) laser welding and induction soldering.

FIG. 29 shows an energy delivery device embodiment of the presentinvention. As shown, an energy delivery device 100 is positioned in thevicinity of an ablation zone 105. As shown, the energy delivery device100 has a cooling tube 110 and cable assembly 120 connected with ahandle 130, which is connected with a cooled probe cannula 140 connectedwith an antenna region 150. As shown, the region between the cooledprobe cannula 140 and the antenna region 150 has therein a stick region160 and a plug region 170. The stick region 160 is designed to attainand maintain a temperature accommodating adherence of a tissue regiononto its surface. The plug region 170 is designed to prevent a reductionin temperature resulting from the cooled probe cannula 140 and the stickregion 160 from affecting (e.g., reducing) the temperature within theantenna region 150. As shown, in these embodiments, the ablation zone105, encompasses both a cooled region of the energy delivery device 100(e.g., the cooled probe cannula 140 and the stick region 160) and anon-cooled region of the energy delivery device 100 (e.g., the plugregion 170 and the antenna region 150).

Energy Delivery Devices with Optimized Characteristic Impedance

In some embodiments, the energy delivery systems of the presentinvention utilize devices configured for delivery of microwave energywith an optimized characteristic impedance (see, e.g., U.S. patentapplication Ser. No. 11/728,428; herein incorporated by reference in itsentirety). Such devices are configured to operate with a characteristicimpedance higher than 50 Ω. (e.g., between 50 and 90 Ω; e.g., higherthan 50, . . . , 55, 56, 57, 58, 59, 60, 61, 62, . . . 90 Ω, preferablyat 77 Ω.).

Energy delivery devices configured to operate with optimizedcharacteristic impedance are particularly useful in terms of tissueablation procedures, and provide numerous advantages over non-optimizeddevices. For example, a major drawback with currently available medicaldevices that utilize microwave energy is the undesired dissipation ofthe energy through transmission lines onto a subject's tissue resultingin undesired burning. Such microwave energy loss results fromlimitations within the design of currently available medical devices.Standard impedance for coaxial transmission lines within medical devicesis 50 . or lower. Generally, coaxial transmission lines with impedancelower than 50 Ω have high amounts of heat loss due to the presence ofdielectric materials with finite conductivity values. As such, medicaldevices with coaxial transmission lines with impedance at 50 Ω or lowerhave high amounts of heat loss along the transmission lines. Inparticular, medical devices utilizing microwave energy transmit energythrough coaxial cables having therein a dielectric material (e.g.,polyfluorothetraethylene or PTFE) surrounding an inner conductor.Dielectric materials such as PTFE have a finite conductivity, whichresult in the undesired heating of transmission lines. This isparticularly true when one supplies the necessary amounts of energy fora sufficient period of time to enable tissue ablation. Energy deliverydevices configured to operate with optimized characteristic impedanceovercome this limitation by lacking, or substantially lacking, a soliddielectric insulator. For example, using air in place of a traditionaldielectric insulator results in an efficient device operating at 77 Ω.In some embodiments, the devices employ a near-zero conductivitydielectric material (e.g., air, water, inert gases, vacuum, partialvacuum, or combinations thereof). The overall temperature of thetransmission lines within such devices are greatly reduced through useof coaxial transmission lines with near-zero conductivity dielectricmaterials, and therefore, greatly reduce undesired tissue heating.

In addition, by providing a coaxial transmission line with a dielectricmaterial having near-zero conductivity, and avoiding the use of typicaldielectric polymers, the coaxial transmission line may be designed suchthat it can fit within small needles (e.g., 18-20 gauge needles).Typically, medical devices configured to delivery microwave energy aredesigned to fit within large needles due to bulky dielectric materials.Microwave ablation has not been extensively applied clinically due tothe large probe size (14 gauge) and relatively small zone of necrosis(1.6 cm in diameter) (Seki T et al., Cancer 74:817 (1994)) that iscreated by the only commercial device (Microtaze, Nippon Shoji, Osaka,Japan. 2.450 MHz, 1.6 mm diameter probe, 70 W for 60 seconds). Otherdevices use a cooling external water jacket that also increases probesize and can increase tissue damage. These large probe sizes increasethe risk of complications when used in the chest and abdomen.

Energy Delivery Devices having Coolant Passage Channels

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices having coolant passagechannels (see, e.g., U.S. Pat. No. 6,461,351, and U.S. patentapplication Ser. No. 11/728,460; herein incorporated by reference in itsentirety). In particular, the energy delivery systems of the presentinvention utilize devices with coaxial transmission lines that allowcooling by flowing a cooling material through the dielectric and/or theinner or outer conductor of the coaxial component. In some embodiments,the devices are configured to minimize the diameter of the device, whilepermitting the passage of the coolant. This is accomplished, in someembodiments, by replacing strips of the inner or outer conductor and/orsolid dielectric material with channels through which a coolant istransferred. In some embodiments, the channels are generated bystripping the outer or inner conductor and/or solid dielectric materialalong the length of the coaxial cable from one or more (e.g., two,three, four) zones. With the removed portions of the outer or innerconductor and/or solid dielectric material creating channels fortransfer of the coolant, the stripped component fits within a smallerouter conductor than it did prior to removal of the outer or innerconductor and/or solid dielectric material. This provides for smallerdevices with all of the advantages derived therefrom. In someembodiments where multiple channels are employed, coolant transfer maybe in alternative directions through one or more of the channels. Anadvantage of such devices is that the diameter of the coaxial cable doesnot need to be increased to accommodate coolant. This permits the use ofcooled devices that are minimally invasive and permit access to regionsof a body that are otherwise inaccessible or accessible only withundesired risk. The use of coolant also permits greater energy deliveryand/or energy deliver for prolonged periods of time. Additional coolingembodiments are described above in the Summary of the Invention.

In some embodiments, the device has a handle attached with the device,wherein the handle is configured to, for example, control the passing ofcoolant into and out of the coolant channels. In some embodiments, thehandle automatically passes coolant into and out of the coolant channelsafter a certain amount of time and/or as the device reaches a certainthreshold temperature. In some embodiments, the handle automaticallystops passage of coolant into and out of the coolant channels after acertain amount of time and/or as the temperature of the device dropsbelow a certain threshold temperature. In some embodiments, the handleis manually controlled to adjust coolant flow.

In some embodiments, the handle has thereon one or more (e.g., 1, 2, 3,4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., display lights (e.g., LEDlights)). In some embodiments, the lights are configured to foridentification purposes. For example, in some embodiments, the lightsare used indicate whether a particular function of the device is activeor inactive. For example, where devices have multiple probes, one ormore lights is used to indicate whether any individual probe is poweredor unpowered. In some embodiments, the lights are used to identify theoccurrence of an event (e.g., the transmission of coolant through thedevice, the transmission of energy through the device, a movement of therespective probe, a change in a setting (e.g., temperature, positioning)within the device, etc.). The handles are not limited to a particularmanner of display (e.g., blinking, alternate colors, solid colors, etc).FIG. 30 shows a device 30000 with three LED lights 31000, 32000, and33000. FIG. 31 shows such a device 30000 in use wherein the device hasthree LED lights 31000, 32000, and 33000.

FIG. 5 shows a schematic drawing of a handle configured to control thepassing of coolant into and out of the coolant channels. As shown inFIG. 5, the handle 500 is engaged with a coaxial transmission line 510having a coolant channel 520. The handle 500 has therein a coolant inputchannel 530, a coolant output channel 540, a first blocking component550 (e.g., a screw or pin) configured to prevent flow through channel520 behind the blocking component and a second blocking component 560.The coolant input channel 530 is configured to provide coolant to thecoolant channel 520. The coolant output channel 540 is configured toremove coolant from the coolant channel 520 (e.g., coolant that hascirculated and removed heat from a device). The coolant input channel530 and coolant output channel 540 are not limited to particular sizesor means for providing and removing coolant. The first blockingcomponents 550 and second blocking component 560 are not limited toparticular sizes or shapes. In some embodiments, the first blockingcomponent 550 and second blocking component 560 each have a circularshape and a size that matches the diameter of the coolant input channel530 and the coolant output channel 540. In some embodiments, the firstblocking component 550 and second blocking component 560 are used toblock the backflow of coolant to a certain region of the handle 500. Insome embodiments, the blocking components are configured such that onlya portion (e.g., 1%, 5%, 10%, 20%, 50%, 75%, 85%, 95%, 99%) of thechannel is blocked. Blocking only a portion permits the user, forexample, to vary the pressure gradients within the coolant channel 520.

Energy delivery devices having coolant passage channels allow foradjustment of the characteristic impedance of the coaxial transmissionline. In particular, the dielectric properties of the coolant (or of anon-coolant material that is passed through the channel(s)) may beadjusted to alter the bulk complex permittivity of the dielectric mediumseparating the outer and inner conductors. As such, changes in thecharacteristic impedance are made during a procedure to, for example,optimize energy delivery, tissue effects, temperature, or other desiredproperties of the system, device, or application. In other embodiments,a flow material is selected prior to a procedure based on the desiredparameters and maintained throughout the entire procedure. Thus, suchdevices provide an antenna radiating in a changing dielectricenvironment to be adjusted to resonate in the changing environment to,for example, allow adaptive tuning of the antenna to ensure peakefficiency of operation. As desired, the fluid flow also allows heattransfer to and from the coaxial cable. In some embodiments, thechannels or hollowed out areas contain a vacuum or partial vacuum. Insome embodiments, impedance is varied by filling the vacuum with amaterial (e.g., any material that provides the desired result).Adjustments may be made at one or more time points or continuously.

The energy delivery devices having coolant passage channels are notlimited to particular aspects of the channels. In some embodiments, thechannel is cut through only a portion of the outer or inner conductorand/or solid dielectric material so that the flowed material is incontact with either the inner or outer conductor and the remainingdielectric material. In some embodiments, the channels are linear alongthe length of the coaxial cable. In some embodiments, the channels arenon-linear. In some embodiments, where more than one channel is used,the channels run parallel to one another. In other embodiments, thechannels are not parallel. In some embodiments, the channels cross oneanother. In some embodiments, the channels remove over 50% (e.g., 60%,70%, 80%, etc.) of the outer or inner conductor and/or solid dielectricmaterial. In some embodiments, the channels remove substantially all ofthe outer or inner conductor and/or solid dielectric material.

The energy delivery devices having coolant passage channels are notlimited by the nature of the material that is flowed through the outeror inner conductor and/or solid dielectric material. In someembodiments, the material is selected to maximize the ability to controlthe characteristic impedance of the device, to maximize heat transfer toor from the coaxial cable, or to optimize a combination of control ofthe characteristic impedance and heat transfer. In some embodiments, thematerial that is flowed through the outer or inner conductor and/orsolid dielectric material is a liquid. In some embodiments, the materialis a gas. In some embodiments, the material is a combination of liquidor gas. The present invention is not limited to the use of liquids orgasses. In some embodiments, the material is a slurry, a gel, or thelike. In some embodiments, a coolant fluid is used. Any coolant fluidnow known or later developed may be used. Exemplary coolant fluidsinclude, but are not limited to, one or more of or combinations of,water, glycol, air, inert gasses, carbon dioxide, nitrogen, helium,sulfur hexafluoride, ionic solutions (e.g., sodium chloride with orwithout potassium and other ions), dextrose in water, Ringer's lactate,organic chemical solutions (e.g., ethylene glycol, diethylene glycol, orpropylene glycol), oils (e.g., mineral oils, silicone oils, fluorocarbonoils), liquid metals, freons, halomethanes, liquified propane, otherhaloalkanes, anhydrous ammonia, sulfur dioxide. In some embodiments, thecoolant fluids are pre-cooled prior to delivery into the energy deliverdevice. In some embodiments, the coolant fluids are cooled with acooling unit following entry into the energy delivery device. In someembodiments, the material passed through the dielectric material isdesigned to generate an endothermic reaction upon contact with anadditional material.

The energy delivery devices having coolant passage channels areconfigured to permit control over the parameters of fluid infusionthrough the device. In some embodiments, the device is manually adjustedby the user (e.g., a treating physician or technician) as desired. Insome embodiments, the adjustments are automated. In some embodiments,the devices are configured with or used with sensors that provideinformation to the user or the automated systems (e.g., comprisingprocessors and/or software configured for receiving the information andadjusting fluid infusion or other device parameters accordingly).Parameters that may be regulated include, but are not limited to, speedof infusion of the fluid, concentration of ions or other components thataffect the properties of the fluid (e.g., dielectric properties, heattransfer properties, flow rate, etc.), temperature of the fluid, type offluid, mixture ratios (e.g., mixtures of gas/fluid for precise tuning orcooling). Thus, energy delivery devices having coolant passage channelsare configured to employ a feed-back loop that can change one or moredesired parameters to tune the device (e.g., antenna) more accurately,or speed up the infusion of the fluid if the device, portions of thedevice, or tissue of the subject reaches an undesired temperature (or atemperature for an undesired period of time).

The energy delivery devices having coolant passage channels providenumerous advantages over the currently available systems and devices.For example, by providing a coaxial transmission line with channelscarved out of, and that can substantially remove the volume of soliddielectric material, the coaxial transmission line may be designed suchthat it can fit within very small needles (e.g., 18-20 gauge needles orsmaller). Typically, medical devices configured to delivery microwaveenergy are designed to fit within large needles due to bulky dielectricmaterials. Other devices use a cooling external water jacket that alsoincreases probe size and can increase tissue damage. These large probesizes increase the risk of complications when used in the chest andabdomen. In some embodiments of the present invention, the maximum outerdiameter of the portion of the device that enters a subject is 16-18gauge or less (20 gauge or less).

FIG. 6 shows a transverse cross-section schematic of standard coaxialcable embodiments and embodiments of the present invention havingcoolant passages. As shown in FIG. 6, a conventional coaxial cable 600and two exemplary coaxial cables of the present invention, 610 and 620are provided. A coaxial cable is made, generally, of three separatespaces: a metallic inner conductor 630, a metallic outer conductor 650,and a space between them. The space between them is usually filled witha low-loss dielectric material 640 (e.g., polyfluorotetraethylene, orPTFE) to mechanically support the inner conductor and maintain it withthe outer conductor. The characteristic impedance of a coaxial cable isfixed by the ratio of diameters of the inner conductor and dielectricmaterial (i.e., inner diameter of the outer conductor) and thepermittivity of the space between them. Usually, the permittivity isfixed because of the solid polymer comprising it. However, inembodiments of the present invention, a fluid with variable permittivity(or conductivity) at least partially occupies this space, permitting thecharacteristic impedance of the cable to be adjusted.

Still referring to FIG. 6, in one embodiment of the present invention,the coaxial cable 610 has the outer portion of the dielectric materialremoved to create a channel between the dielectric material 640 and theouter conductor 650. In the embodiments shown, the created space isseparated into four distinct channels 670 by the addition of supportlines 660 configured to maintain the space between the outer conductor650 and the solid dielectric material 640. The support lines 660 may bemade of any desired material and may be the same or a different materialas the solid dielectric material 640. In some embodiments, so as toavoid undesired heating of the device (e.g., undesired heating of theouter conductor), the support lines 660 are made of a biocompatible andmeltable material (e.g., wax). The presence of multiple channels permitsone or more of the channels to permit flow in one direction (towards theproximal end of the cable) and one or more other channels to permit flowin the opposite direction (towards the distal end of the cable).

Still referring to FIG. 6, in another embodiment, the coaxial cable 620has a substantial portion of the solid dielectric material 640 removed.Such an embodiment may be generated, for example, by stripping away thesolid dielectric material 640 down to the surface of inner conductor 630on each of four sides. In another embodiment, strips of dielectricmaterial 640 are applied to an inner conductor 630 to create thestructure. In this embodiment, four channels 670 are created. Byremoving a substantial amount of the dielectric material 640, thediameter of the outer conductor 650 is substantially reduced. Thecorners provided by the remaining dielectric material 640 provide thesupport to maintain the position of the outer conductor 650 with respectto the inner conductor 630. In this embodiment, the overall diameter ofthe coaxial cable 620 and the device is substantially reduced.

In some embodiments, the devices have a coolant passage formed throughinsertion of a tube configured to circulate coolant through thedielectric portion or inner or outer conductors of any of the energyemission devices of the present invention. FIG. 7 shows a coolantcirculating tube 700 (e.g., coolant needle, catheter) positioned withinan energy emission device 710 having an outer conductor 720, adielectric material 730, and an inner conductor 740. As shown in FIG. 7,the tube 700 is positioned along the outside edge of the dielectricmaterial 730 and inside edge of the outer conductor 720, with the innerconductor 740 positioned approximately in the center of the dielectricmaterial 730. In some embodiments, the tube 700 is positioned within thedielectric material 730 such that it does not contact the outerconductor 720. In some embodiments, the tube 700 has multiple channels(not shown) for purposes of recirculating the coolant within the tube700 without passing the coolant into the dielectric material 730 and/orthe outer conductor 720, thereby cooling the dielectric material 730and/or the outer conductor 720 with the exterior of the tube 700.

Energy Delivery Device with a Center Fed Dipole

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices employing a center fed dipolecomponent (see, e.g., U.S. patent application Ser. No. 11/728,457;herein incorporated by reference in its entirety). The devices are notlimited to particular configurations. In some embodiments, the deviceshave therein a center fed dipole for heating a tissue region throughapplication of energy (e.g., microwave energy). In some embodiments,such devices have a coaxial cable connected to a hollow tube (e.g.,where the interior diameter is at least 50% of the exterior diameter;e.g., where the interior diameter is substantially similar to theexterior diameter). The coaxial cable may be a standard coaxial cable,or it may be a coaxial cable having therein a dielectric component witha near-zero conductivity (e.g., air). The hollow tube is not limited toa particular design configuration. In some embodiments, the hollow tubeassumes the shape of (e.g., diameter of), for example, a 20-gaugeneedle. Preferably, the hollow tube is made of a solid, rigid conductivematerial (e.g., any number of metals, conductor-coated ceramics orpolymers, etc.). In some embodiments, the hollow tube is configured witha sharpened point or the addition of a stylet on its distal end topermit direct insertion of the device into a tissue region without theuse of, for example, a cannula. The hollow tube is not limited to aparticular composition (e.g., metal, plastic, ceramic). In someembodiments, the hollow tube comprises, for example, copper or copperalloys with other hardening metals, silver or silver alloys with otherhardening metals, gold-plated copper, metal-plated Macor (machinableceramic), metal-plated hardened polymers, and/or combinations thereofThe stylet tip may be made of any material. In some embodiments, the tipis made from hardened resin. In some embodiments, the tip is metal. Insome embodiments, the stylet tip is made from titanium or an equivalentof titanium. In some embodiments, the stylet tip is braised to zirconiaor an equivalent of zirconia. In some such embodiments, the metal tip isan extension of a metal portion of an antenna and is electricallyactive.

In some embodiments, the center fed dipole is configured to adjust theenergy delivery characteristics in response to heating so as to providea more optimal energy delivery throughout the time period of a process.In some embodiments, this is achieved by using a material that changesvolume in response to temperature changes such that the change in thevolume of the material changes to the energy delivery characteristics ofthe device. In some embodiments, for example, an expandable material isplaced in the device such that the resonant portion of the center feddipole component or the stylet is pushed distally along the device inresponse to heating. This changes the tuning of the device to maintain amore optimal energy delivery. The maximum amount of movement can beconstrained, if desired, by, for example, providing a locking mechanismthat prevents extension beyond a particular point. The energy deliverydevices employing a center fed dipole component are not limited by themanner in which the hollow tube is connected to the coaxial cable. Insome embodiments, a portion of the outer conductor at the distal end ofthe coaxial cable feedline is removed, exposing a region of soliddielectric material. The hollow tube can be positioned onto the exposeddielectric material and attached by any means. In some embodiments, aphysical gap between the outer conductor and the hollow tube isprovided. In some embodiments, the hollow tube is capacitively orconductively attached to the feedline at its center point such that theelectrical length of the hollow tube comprises a frequency-resonantstructure when inserted into tissue.

In use, the energy delivery devices employing a center fed dipolecomponent are configured such that an electric field maximum isgenerated at the open distal end of the hollow tube. In someembodiments, the distal end of the hollow tube has a pointed shape so asto assist in inserting the device though a subject and into a tissueregion. In some embodiments, the entire device is hard and rigid so asto facilitate linear and direct insertion directly to a target site. Insome embodiments, the structure resonates at, for example, ˜2.45 GHz, ascharacterized by a minimum in the reflection coefficient (measured atthe proximal end of the feedline) at this frequency. By changing thedimensions of the device (e.g., length, feed point, diameter, gap, etc.)and materials (dielectric materials, conductors, etc.) of the antenna,the resonant frequency may be changed. A low reflection coefficient at adesired frequency ensures efficient transmission of energy from theantenna to the medium surrounding it.

Preferably, the hollow tube is of length .λ/2, where λ is theelectromagnetic field wavelength in the medium of interest (e.g., ˜18 cmfor 2.45 GHz in liver) to resonate within the medium. In someembodiments, the length of the hollow tube is approximately λ/2, where λis the electromagnetic field wavelength in the medium of interest toresonate within the medium, such that a minimum of power reflection atthe proximal end is measured. However, deviations from this length maybe employed to generate resonant wavelengths (e.g., as the surroundingmaterials are changed). Preferably, the inner conductor of a coaxialcable is extended with its distal end at the tube center (e.g., at λ/4from the end of the tube) and configured such that the inner conductormaintains electrical contact at the tube center, although deviationsfrom this position are permitted (e.g., to generate resonantwavelengths).

The hollow tube portion of the present invention may have a wide varietyof shapes. In some embodiments, the tube is cylindrical throughout itslength. In some embodiments, tube tapers from a center position suchthat it has a smaller diameter at its end as compared to its center.Having a smaller point at the distal end assists in penetrating asubject to arrive at the target region. In some embodiments, where theshape of the hollow tube deviates from a cylindrical shape, the tubemaintains a symmetrical structure on either side of its longitudinalcenter. However, the devices are not limited by the shape of the hollowtube, so long as the functional properties are achieved (i.e., theability to deliver desired energy to a target region).

In some embodiments, the center-fed dipole components may be added tothe distal end of a wide variety of ablation devices to provide thebenefits described herein. Likewise, a wide variety of devices may bemodified to accept the center-fed dipole components of the presentinvention.

In some embodiments, the devices have a small outer diameter. In someembodiments, the center-fed dipole component of the invention isdirectly used to insert the invasive component of the device into asubject. In some such embodiments, the device does not contain acannula, allowing for the invasive components to have a smaller outerdiameter. For example, the invasive component can be designed such thatit fits within or is the size of very small needles (e.g., 18-20 gaugeneedles or smaller).

FIG. 8 schematically shows the distal end of a device 800 (e.g., antennaof an ablation device) of the present invention that comprises a centerfed dipole component 810 of the present invention. One skilled in theart will appreciate any number of alternative configurations thataccomplish the physical and/or functional aspects of the presentinvention. As shown, the center fed dipole device 800 has therein ahollow tube 815, a coaxial transmission line 820 (e.g., a coaxialcable), and a stylet 890. The center fed dipole device 800 is notlimited to a particular size. In some embodiments, the size of thecenter fed dipole device 800 is small enough to be positioned at atissue region (e.g., a liver) for purposes of delivering energy (e.g.,microwave energy) to that tissue region.

Referring again to FIG. 8, the hollow tube 815 is not limited to aparticular material (e.g., plastic, ceramic, metal, etc.). The hollowtube 815 is not limited to a particular length. In some embodiments, thelength of the hollow tube is λ/2, where λ is the electromagnetic fieldwavelength in the medium of interest (e.g., ˜18 cm for 2.45 GHz inliver). The hollow tube 815 engages the coaxial transmission line 820such that the hollow tube 815 is attached to the coaxial transmissionline 820 (described in more detail below). The hollow tube 815 hastherein a hollow tube matter 860. The hollow tube 815 is not limited toa particular type of hollow tube matter. In some embodiments, the hollowtube matter 860 is air, fluid or a gas.

Still referring to FIG. 8, the hollow tube 815 is not limited to aparticular shape (e.g., cylindrical, triangular, squared, rectangular,etc.). In some embodiments, the shape of the hollow tube 815 is of aneedle (e.g., a 20-gauge needle, an 18-gauge needle). In someembodiments, the hollow tube 815 is divided into two portions each ofvariable length. As shown, the hollow tube 815 is divided into twoportions each of equal length (e.g., each portion having a length ofλ/4). In such embodiments, the shapes of each portion are symmetrical.In some embodiments, the hollow tube has a diameter equal to or lessthan a 20-gauge needle, a 17-gauge needle, a 12-gauge needle, etc.

Still referring to FIG. 8, the distal end of the hollow tube 815 engagesa stylet 890. The device 800 is not limited to a particular stylet 890.In some embodiments, the stylet 890 is designed to facilitatepercutaneous insertion of the device 800. In some embodiments, thestylet 890 engages the hollow tube 815 by sliding inside the hollow tube815 such that the stylet 890 is secured. In some embodiments, the stylet890 may be made of any material. In some embodiments, the stylet 890 ismade from hardened resin. In some embodiments, the stylet 890 is metal.In some embodiments, the stylet 890 is made from titanium or anequivalent of titanium. In some embodiments, the stylet 890 is braisedto zirconia or an equivalent of zirconia. In some such embodiments, thestylet 890 is an extension of a metal portion of an antenna and iselectrically active.

Still referring to FIG. 8, the coaxial transmission line 820 is notlimited to a particular type of material. In some embodiments, theproximal coaxial transmission line 820 is constructed fromcommercial-standard 0.047-inch semi-rigid coaxial cable. In someembodiments, the coaxial transmission line 820 is metal-plated (e.g.,silver-plated, copper-plated), although the present invention is not solimited. The proximal coaxial transmission line 820 is not limited to aparticular length.

Still referring to FIG. 8, in some embodiments, the coaxial transmissionline 820 has a coaxial center conductor 830, a coaxial dielectricmaterial 840, and a coaxial outer conductor 850. In some embodiments,the coaxial center conductor 830 is configured to conduct cooling fluidalong its length. In some embodiments, the coaxial center conductor 830is hollow. In some embodiments, the coaxial center conductor 830 has adiameter of, for example, 0.012 inches. In some embodiments, the coaxialdielectric material 840 is polyfluorotetraethylene (PTFE). In someembodiments, the coaxial dielectric material 840 has a near-zeroconductivity (e.g., air, fluid, gas).

Still referring to FIG. 8, the distal end of the coaxial transmissionline 820 is configured to engage the proximal end of the hollow tube815. In some embodiments, the coaxial center conductor 830 and thecoaxial dielectric material 840 extend into the center of the hollowtube 815. In some embodiments, the coaxial center conductor 820 extendsfurther into the hollow tube 815 than the coaxial dielectric material840. The coaxial center conductor 820 is not limited to a particularamount of extension into the hollow tube 815. In some embodiments, thecoaxial center conductor 820 extends a length of ./4 into the hollowtube 815. The distal end of the coaxial transmission line 820 is notlimited to a particular manner of engaging the proximal end of thehollow tube 815. In some embodiments, the proximal end of the hollowtube engages the coaxial dielectric material 840 so as to secure thehollow tube 815 with the coaxial transmission line 820. In someembodiments, where the coaxial dielectric material 840 has a near-zeroconductivity, the hollow tube 815 is not secured with the coaxialtransmission line 820. In some embodiments, the distal end of thecoaxial center conductor 830 engages the walls of the hollow tube 815directly or through contact with a conductive material 870, which may bemade of the same material as the coaxial center conductor or may be of adifferent material (e.g., a different conductive material).

Still referring to FIG. 8, in some embodiments, a gap 880 exists betweenthe distal end of the coaxial transmission line outer conductor 850 andthe hollow tube 815 thereby exposing the coaxial dielectric material840. The gap 880 is not limited to a particular size or length. In someembodiments, the gap 880 ensures an electric field maximum at theproximal end of the coaxial transmission line 880 and the distal openend of the hollow tube 815. In some embodiments, the center fed dipoledevice 810 resonates at ˜2.45 GHz, as characterized by a minimum in thereflection coefficient at this frequency. By changing the dimensions(length, feed point, diameter, gap, etc.) and materials (dielectricmaterials, conductors, etc.) of the device the resonant frequency may bechanged. A low reflection coefficient at this frequency ensuresefficient transmission of energy from the antenna to the mediumsurrounding it.

Still referring to FIG. 8, in some embodiments, the gap 880 is filledwith a material (e.g., epoxy) so bridge the coaxial transmission line820 and the hollow tube 815. The devices are not limited to a particulartype or kind of substantive material. In some embodiments, thesubstantive material does not interfere with the generation or emissionof an energy field through the device. In some embodiments, the materialis biocompatible and heat resistant. In some embodiments, the materiallacks or substantially lacks conductivity. In some embodiments, thematerial further bridges the coaxial transmission line 820 and thehollow tube 815 with the coaxial center conductor 830. In someembodiments, the substantive material is a curable resin. In someembodiments, the material is a dental enamel (e.g., XRV Herculiteenamel; see, also, U.S. Pat. Nos. 6,924,325, 6,890,968, 6,837,712,6,709,271, 6,593,395, and 6,395,803, each herein incorporated byreference in their entireties). In some embodiments, the substantivematerial is cured (e.g., cured with a curing light such as, for example,L.E. Demetron II curing light) (see, e.g., U.S. Pat. Nos. 6,994,546,6,702,576, 6,602,074 and 6,435,872). Thus, the present inventionprovides ablation devices comprising a cured enamel resin. Such a resinis biocompatible and rigid and strong.

Energy Delivery Devices having a Linear Array of Antenna Components

In some embodiments, the energy delivery systems of the presentinvention utilize energy delivery devices having a linear array ofantennae components (see, e.g., U.S. Provisional Patent Application No.60/831,055; herein incorporated by reference in its entirety). Thedevices are not limited to particular configurations. In someembodiments, the energy delivery devices having a linear array ofantennae components have therein an antenna comprising an innerconductor and an outer conductor, wherein the outer conductor isprovided in two or more linear segments separated by gaps, such that thelength and position of the segments is configured for optimized deliveryof energy at the distal end of the antenna. For example, in someembodiments, an antenna comprises a first segment of outer conductorthat spans the proximal end of the antenna to a region near the distalend and a second segment of outer conductor distal to the first segmentwherein a gap separates or partially separates the first and secondsegments. The gaps may entirely circumscribe the outer conductor or mayonly partially circumscribe the outer conductor. In some embodiments,the length of the second segment is .λ/2, λ/4, etc., although thepresent invention is not so limited. In some embodiments one or moreadditional (e.g., third, fourth, fifth) segments are provided distal tothe second segment, each of which is separated from the other by a gap.In some embodiments, the antenna is terminated with a conductiveterminal end that is in electronic communication with the innerconductor. In some embodiments, the conductive terminal end comprises adisc having a diameter substantially identical to the diameter of theouter conductor. Such antennae provide multiple peaks of energy deliveryalong the length of the distal end of the antenna, providing a broaderregion of energy delivery to target larger regions of tissue. Thelocation and position of the peaks is controlled by selecting the lengthof the outer conductor segments and by controlling the amount of energydelivered.

The energy delivery devices having a linear array of antennae componentsare not limited by the nature of the various components of the antenna.A wide variety of components may be used to provide optimal performance,including, but not limited to, the use of a variety of materials for theinner and outer conductors, the use of a variety of materials andconfigurations for dielectric material between the inner and outerconductors, the use of coolants provided by a variety of differentmethods.

In certain embodiments, the devices comprise a linear antenna, whereinthe linear antenna comprises an outer conductor enveloped around aninner conductor, wherein the inner conductor is designed to receive andtransmit energy (e.g., microwave energy), wherein the outer conductorhas therein a series of gap regions (e.g., at least two) positionedalong the outer conductor, wherein the inner conductor is exposed at thegap regions, wherein the energy transmitting along the inner conductoris emitted through the gap regions. The devices are not limited to aparticular number of gap regions (e.g., 2, 3, 4, 5, 6, 10, 20, 50). Insome embodiments, the positioning of the gaps is configured for, forexample, linear ablation. In some embodiments, the inner conductorcomprises a dielectric layer enveloping a central transmission line. Insome embodiments, the dielectric element has near-zero conductivity. Insome embodiments, the device further comprises a stylet. In someembodiments, the device further comprises a tuning element for adjustingthe amount of energy delivered through the gap regions. In certainembodiments, when used in tissue ablation settings, the device isconfigured to deliver a sufficient amount of energy to ablate a tissueregion or cause thrombosis.

The energy delivery devices having a linear array of antennae componentsprovide numerous advantages over the currently available systems anddevices. For example, a major drawback with currently available medicaldevices that utilize microwave energy is that the emitted energy isprovided locally, thereby precluding delivery of energy over a deeperand denser scale. The devices of the present invention overcome thislimitation by providing an applicator device having a linear array ofantennae components configured to deliver energy (e.g., microwaveenergy) over a wider and deeper scale (e.g., as opposed to localdelivery).

Such a device is particularly useful in the tissue ablation of denseand/or thick tissue regions (e.g., tumors, organ lumens) andparticularly deep tissue regions (e.g., large cardiac areas, brains,bones).

III. Processor

In some embodiments, the energy delivery systems of the presentinvention utilize processors that monitor and/or control and/or providefeedback concerning one or more of the components of the system. In someembodiments, the processor is provided within a computer module. Thecomputer module may also comprise software that is used by the processorto carry out one or more of its functions. For example, in someembodiments, the systems of the present invention provide software forregulating the amount of microwave energy provided to a tissue regionthrough monitoring one or more characteristics of the tissue regionincluding, but not limited to, the size and shape of a target tissue,the temperature of the tissue region, and the like (e.g., through afeedback system) (see, e.g., U.S. patent application Ser. Nos.11/728,460, 11/728,457, and 11/728,428; each of which is hereinincorporated by reference in their entireties). In some embodiments, thesoftware is configured to provide information (e.g., monitoringinformation) in real time. In some embodiments, the software isconfigured to interact with the energy delivery systems of the presentinvention such that it is able to raise or lower (e.g., tune) the amountof energy delivered to a tissue region. In some embodiments, thesoftware is designed to prime coolants for distribution into, forexample, an energy delivery device such that the coolant is at a desiredtemperature prior to use of the energy delivery device. In someembodiments, the type of tissue being treated (e.g., liver) is inputtedinto the software for purposes of allowing the processor to regulate(e.g., tune) the delivery of microwave energy to the tissue region basedupon pre-calibrated methods for that particular type of tissue region.In other embodiments, the processor generates a chart or diagram basedupon a particular type of tissue region displaying characteristicsuseful to a user of the system. In some embodiments, the processorprovides energy delivering algorithms for purposes of, for example,slowly ramping power to avoid tissue cracking due to rapid out-gassingcreated by high temperatures. In some embodiments, the processor allowsa user to choose power, duration of treatment, different treatmentalgorithms for different tissue types, simultaneous application of powerto the antennas in multiple antenna mode, switched power deliverybetween antennas, coherent and incoherent phasing, etc. In someembodiments, the processor is configured for the creation of a databaseof information (e.g., required energy levels, duration of treatment fora tissue region based on particular patient characteristics) pertainingto ablation treatments for a particular tissue region based uponprevious treatments with similar or dissimilar patient characteristics.In some embodiments, the processor is operated by remote control.

In some embodiments, the processor is used to generate, for example, anablation chart based upon entry of tissue characteristics (e.g., tumortype, tumor size, tumor location, surrounding vascular information,blood flow information, etc.). In such embodiments, the processor coulddirect placement of the energy delivery device so as to achieve desiredablation based upon the ablation chart.

In some embodiments a software package is provided to interact with theprocessor that allows the user to input parameters of the tissue to betreated (e.g., type of tumor or tissue section to be ablated, size,where it is located, location of vessels or vulnerable structures, andblood flow information) and then draw the desired ablation zone on a CTor other image to provide the desired results. The probes may be placedinto the tissue, and the computer generates the expected ablation zonebased on the information provided. Such an application may incorporatefeedback. For example, CT, MRI, or ultrasound imaging or thermometry maybe used during the ablation. This data is fed back into the computer,and the parameters readjusted to produce the desired result.

In some embodiments, user interface software is provided for monitoringand/or operating the components of the energy delivery systems. In someembodiments, the user interface software is operated by a touch screeninterface. In some embodiments, the user interface software may beimplemented and operated within a sterile setting (e.g., a procedureroom) or in a non-sterile setting. In some embodiments, the userinterface software is implemented and operated within a procedure devicehub (e.g., via a processor). In some embodiments, the user interfacesoftware is implemented and operated within a procedure cart (e.g., viaa processor). The user interface software is not limited to particularfunctions. Examples of functions associated with the user interfacesoftware include, but are not limited to, tracking the number of usesper component within the energy delivery system (e.g., tracking thenumber of times an energy delivery device is used), providing andtracking real time temperatures of each component or parts of eachcomponent (e.g., providing real time temperature of different locationsalong an energy delivery device (e.g., at the handle, at the stick, atthe tip)) (e.g., providing real time temperature of the cablesassociated with the energy delivery systems), providing and trackingreal time temperature of the tissue being treated, providing anautomatic shut off for the part or all of the energy delivery system(e.g., an emergency shut off), generation of reports based upon the dataaccumulated, for example, prior to, during and after a procedure,providing audible and/or visual alerts to a user (e.g., alertsindicating a procedure has begun and/or is finished, alerts indicating atemperature has reached an aberrant level, alerts indicating the lengthof the procedure has gone beyond a default, etc.). FIGS. 32A, B and Cshow examples of user interface software for the energy delivery systemsof the present invention. As shown in FIG. 32A, the user interfacesoftware is designed to display and permit adjustment of the time,temperature, type of operation (e.g., test, stick, stop ablate, andcauterize), and power for each probe (e.g., energy delivery device).FIG. 32B shows a report generated with the user interface softwareshowing the power, elapsed time, and target time, and related messages.FIG. 32C shows user interface tools associated with the user interfacesoftware including a system log with notes, a system diagnostic log, aprocedure history, the default time, default power, monitor brightness,time setting, and additional functions (e.g., time display options, timezone options, call home options, time setting options, and audio volumeoptions).

As used herein, the terms “computer memory” and “computer memory device”refer to any storage media readable by a computer processor. Examples ofcomputer memory include, but are not limited to, random access memory(RAM), read-only memory (ROM), computer chips, optical discs (e.g.,compact discs (CDs), digital video discs (DVDs), etc.), magnetic disks(e.g., hard disk drives (HDDs), floppy disks, ZIP.RTM. disks, etc.),magnetic tape, and solid state storage devices (e.g., memory cards,“flash” media, etc.).

As used herein, the term “computer readable medium” refers to any deviceor system for storing and providing information (e.g., data andinstructions) to a computer processor. Examples of computer readablemedia include, but are not limited to, optical discs, magnetic disks,magnetic tape, solid-state media, and servers for streaming media overnetworks. As used herein, the terms “processor” and “central processingunit” or “CPU” are used interchangeably and refer to a device that isable to read a program from a computer memory device (e.g., ROM or othercomputer memory) and perform a set of steps according to the program.

IV. Imaging Systems

In some embodiments, the energy delivery systems of the presentinvention utilize imaging systems comprising imaging devices. The energydelivery systems are not limited to particular types of imaging devices(e.g., endoscopic devices, stereotactic computer assisted neurosurgicalnavigation devices, thermal sensor positioning systems, motion ratesensors, steering wire systems, intraprocedural ultrasound, interstitialultrasound, microwave imaging, acoustic tomography, dual energy imaging,fluoroscopy, computerized tomography magnetic resonance imaging, nuclearmedicine imaging devices triangulation imaging, thermoacoustic imaging,infrared and/or laser imaging, electromagnetic imaging) (see, e.g., U.S.Pat. Nos. 6,817,976, 6,577,903, and 5,697,949, 5,603,697, andInternational Patent Application No. WO 06/005,579; each hereinincorporated by reference in their entireties). In some embodiments, thesystems utilize endoscopic cameras, imaging components, and/ornavigation systems that permit or assist in placement, positioning,and/or monitoring of any of the items used with the energy systems ofthe present invention.

In some embodiments, the energy delivery systems provide software isconfigured for use of imaging equipment (e.g., CT, MRI, ultrasound). Insome embodiments, the imaging equipment software allows a user to makepredictions based upon known thermodynamic and electrical properties oftissue, vasculature, and location of the antenna(s). In someembodiments, the imaging software allows the generation of athree-dimensional map of the location of a tissue region (e.g., tumor,arrhythmia), location of the antenna(s), and to generate a predicted mapof the ablation zone.

In some embodiments, the imaging systems of the present invention areused to monitor ablation procedures (e.g., microwave thermal ablationprocedures, radio-frequency thermal ablation procedures). The presentinvention is not limited to a particular type of monitoring. In someembodiments, the imaging systems are used to monitor the amount ofablation occurring within a particular tissue region(s) undergoing athermal ablation procedure. In some embodiments, the monitoring operatesalong with the ablation devices (e.g., energy delivery devices) suchthat the amount of energy delivered to a particular tissue region isdependent upon the imaging of the tissue region. The imaging systems arenot limited to a particular type of monitoring. The present invention isnot limited to what is being monitored with the imaging devices. In someembodiments, the monitoring is imaging blood perfusion for a particularregion so as to detect changes in the region, for example, before,during and after a thermal ablation procedure. In some embodiments, themonitoring includes, but is not limited to, MRI imaging, CT imaging,ultrasound imaging, nuclear medicine imaging, and fluoroscopy imaging.For example, in some embodiments, prior to a thermal ablation procedure,a contrast agent (e.g., iodine or other suitable CT contrast agent;gadolinium chelate or other suitable MRI contrast agent, microbubbles orother suitable ultrasound contrast agent, etc.) is supplied to a subject(e.g., a patient) and the contrast agent perfusing through a particulartissue region that is undergoing the ablation procedure is monitored forblood perfusion changes. In some embodiments, the monitoring isqualitative information about the ablation zone properties (e.g., thediameter, the length, the cross-sectional area, the volume). The imagingsystem is not limited to a particular technique for monitoringqualitative information. In some embodiments, techniques used to monitorqualitative information include, but are not limited to, non-imagingtechniques (e.g., time-domain reflectometry, time-of-flight pulsedetection, frequency-modulated distance detection, eigenmode orresonance frequency detection or reflection and transmission at anyfrequency, based on one interstitial device alone or in cooperation withother interstitial devices or external devices). In some embodiments,the interstitial device provides a signal and/or detection for imaging(e.g., electro-acoustic imaging, electromagnetic imaging, electricalimpedance tomography). In some embodiments, non-imaging techniques areused to monitor the dielectric properties of the medium surrounding theantenna, detect an interface between the ablated region and normaltissue through several means, including resonance frequency detection,reflectometry or distance-finding techniques, powerreflection/transmission from interstitial antennas or external antennas,etc. In some embodiments, the qualitative information is an estimate ofablation status, power delivery status, and/or simple go/no-go checks toensure power is being applied. In some embodiments, the imaging systemsare designed to automatically monitor a particular tissue region at anydesired frequency (e.g., per second intervals, per one-minute intervals,per ten-minute intervals, per hour-intervals, etc.). In someembodiments, the present invention provides software designed toautomatically obtain images of a tissue region (e.g., MRI imaging, CTimaging, ultrasound imaging, nuclear medicine imaging, fluoroscopyimaging), automatically detect any changes in the tissue region (e.g.,blood perfusion, temperature, amount of necrotic tissue, etc.), andbased on the detection to automatically adjust the amount of energydelivered to the tissue region through the energy delivery devices.Likewise, an algorithm may be applied to predict the shape and size ofthe tissue region to be ablated (e.g., tumor shape) such that the systemrecommends the type, number, and location of ablation probes toeffectively treat the region. In some embodiments, the system isconfigured to with a navigation or guidance system (e.g., employingtriangulation or other positioning routines) to assist in or direct theplacement of the probes and their use.

For example, such procedures may use the enhancement or lack ofenhancement of a contrast material bolus to track the progress of anablation or other treatment procedure. Subtraction methods may also beused (e.g., similar to those used for digital subtraction angiography).For example, a first image may be taken at a first time point.Subsequent images subtract out some or all of the information from thefirst image so that changes in tissue are more readily observed.Likewise, accelerated imaging techniques may be used that apply “undersampling” techniques (in contrast to Nyquist sampling). It iscontemplated that such techniques provide excellent signal-to-noiseusing multiple low resolutions images obtained over time. For example,an algorithm called HYPER (highly constrained projection reconstruction)is available for MRI that may be applied to embodiments of the systemsof the invention.

As thermal-based treatments coagulate blood vessels when tissuetemperatures exceed, for example, 50° C., the coagulation decreasesblood supply to the area that has been completely coagulated. Tissueregions that are coagulated do not enhance after the administration ofcontrast. In some embodiments, the present invention utilizes theimaging systems to automatically track the progress of an ablationprocedure by giving, for example, a small test injection of contrast todetermine the contrast arrival time at the tissue region in question andto establish baseline enhancement. In some embodiments, a series ofsmall contrast injections is next performed following commencement ofthe ablation procedure (e.g., in the case of CT, a series of up tofifteen 10 ml boluses of 300 mgI/ml water soluble contrast is injected),scans are performed at a desired appropriate post-injection time (e.g.,as determined from the test injection), and the contrast enhancement ofthe targeted area is determined using, for example, a region-of-interest(ROI) to track any one of a number of parameters including, but notlimited to, attenuation (Hounsfield Units [HU]) for CT, signal (MRI),echogenicity (ultrasound), etc. The imaged data is not limited to aparticular manner of presentation. In some embodiments, the imaging datais presented as color-coded or grey scale maps or overlays of the changein attenuation/signal/echogenicity, the difference between targeted andnon-targeted tissue, differences in arrival time of the contrast bolusduring treatment, changes in tissue perfusion, and any other tissueproperties that can be measured before and after the injection ofcontrast material. The methods of the present invention are not limitedto selected ROI's, but can be generalized to all pixels within anyimage. The pixels can be color-coded, or an overlay used to demonstratewhere tissue changes have occurred and are occurring. The pixels canchange colors (or other properties) as the tissue property changes, thusgiving a near real-time display of the progress of the treatment. Thismethod can also be generalized to 3d/4d methods of image display.

In some embodiments, the area to be treated is presented on a computeroverlay, and a second overlay in a different color or shading yields anear real-time display of the progress of the treatment. In someembodiments, the presentation and imaging is automated so that there isa feedback loop to a treatment technology (RF, MW, HIFU, laser, cryo,etc) to modulate the power (or any other control parameter) based on theimaging findings. For example, if the perfusion to a targeted area isdecreased to a target level, the power could be decreased or stopped.For example, such embodiments are applicable to a multiple applicatorsystem as the power/time/frequency/duty cycle, etc. is modulated foreach individual applicator or element in a phased array system to createa precisely sculpted zone of tissue treatment. Conversely, in someembodiments, the methods are used to select an area that is not to betreated (e.g., vulnerable structures that need to be avoided such asbile ducts, bowel, etc.). In such embodiments, the methods monitortissue changes in the area to be avoided, and warn the user (e.g.,treating physician) using alarms (e.g., visible and/or audible alarms)that the structure to be preserved is in danger of damage. In someembodiments, the feedback loop is used to modify power or any otherparameter to avoid continued damage to a tissue region selected not tobe treated. In some embodiments, protection of a tissue region fromablation is accomplished by setting a threshold value such as a targetROI in a vulnerable area, or using a computer overlay to define a “notreatment” zone as desired by the user.

V. Tuning Systems

In some embodiments, the energy delivery systems of the presentinvention utilize tuning elements for adjusting the amount of energydelivered to the tissue region. In some embodiments, the tuning elementis manually adjusted by a user of the system. In some embodiments, atuning system is incorporated into an energy delivery device so as topermit a user to adjust the energy delivery of the device as desired(see, e.g., U.S. Pat. Nos. 5,957969, 5,405,346; each herein incorporatedby reference in their entireties). In some embodiments, the device ispretuned to the desired tissue and is fixed throughout the procedure. Insome embodiments, the tuning system is designed to match impedancebetween a generator and an energy delivery device (see, e.g., U.S. Pat.No. 5,364,392; herein incorporated by reference in its entirety). Insome embodiments, the tuning element is automatically adjusted andcontrolled by a processor of the present invention (see, e.g., U.S. Pat.No. 5,693,082; herein incorporated by reference in its entirety). Insome embodiments, a processor adjusts the energy delivery over time toprovide constant energy throughout a procedure, taking into account anynumber of desired factors including, but not limited to, heat, natureand/or location of target tissue, size of lesion desired, length oftreatment time, proximity to sensitive organ areas or blood vessels, andthe like. In some embodiments, the system comprises a sensor thatprovides feedback to the user or to a processor that monitors thefunction of the device continuously or at time points. The sensor mayrecord and/or report back any number of properties, including, but notlimited to, heat at one or more positions of a components of the system,heat at the tissue, property of the tissue, and the like. The sensor maybe in the form of an imaging device such as CT, ultrasound, magneticresonance imaging, or any other imaging device. In some embodiments,particularly for research application, the system records and stores theinformation for use in future optimization of the system generallyand/or for optimization of energy delivery under particular conditions(e.g., patient type, tissue type, size and shape of target region,location of target region, etc.).

VI. Temperature Adjustment Systems

In some embodiments, the energy delivery systems of the presentinvention utilize coolant systems so as to reduce undesired heatingwithin and along an energy delivery device (e.g., tissue ablationcatheter). The systems of the present invention are not limited to aparticular cooling system mechanism. In some embodiments, the systemsare designed to circulate a coolant (e.g., air, liquid, etc.) throughoutan energy delivery device such that the coaxial transmission line(s) andantenna(e) temperatures are reduced. In some embodiments, the systemsutilize energy delivery devices having therein channels designed toaccommodate coolant circulation. In some embodiments, the systemsprovide a coolant sheath wrapped around the antenna or portions of theantenna for purposes of cooling the antenna externally (see, e.g., U.S.patent application Ser. No. 11/053,987; herein incorporated by referencein its entirety). In some embodiments, the systems utilize energydelivery devices having a conductive covering around the antenna forpurposes of limiting dissipation of heat onto surrounding tissue (see,e.g., U.S. Pat. No. 5,358,515; herein incorporated by reference in itsentirety). In some embodiments, upon circulation of the coolant, it isexported into, for example, a waste receptacle. In some embodiments,upon circulation of the coolant it is recirculated. In some embodiments,the coolant is a gas circulated at or near its critical point. In someembodiments, the gas delivered at or near its critical point is carbondioxide gas. In some embodiments, the energy delivery devices areconfigured to compress transported coolants (e.g., carbon dioxide gas ator near its critical point) at a desired pressure so as to retain thecoolant at or near its critical point.

In some embodiments, the systems utilize expandable balloons inconjunction with energy delivery devices for purposes of urging tissueaway from the surface of the antenna(e) (see, e.g., U.S. patentapplication Ser. No. 11/053,987; herein incorporated by reference in itsentirety).

In some embodiments, the systems utilize devices configured to attachonto an energy delivery device for purposes of reducing undesiredheating within and along the energy delivery device (see, e.g., U.S.patent application Ser. No. 11/237,430; herein incorporated by referencein its entirety).

VII. Identification Systems

In some embodiments, the energy delivery systems of the presentinvention utilize identification elements (e.g., RFID elements,identification rings (e.g., fidicials), barcodes, etc.) associated withone or more components of the system. In some embodiments, theidentification element conveys information about a particular componentof the system. The present invention is not limited by the informationconveyed. In some embodiments, the information conveyed includes, but isnot limited to, the type of component (e.g., manufacturer, size, energyrating, tissue configuration, etc.), whether the component has been usedbefore (e.g., so as to ensure that non-sterile components are not used),the location of the component, patient-specific information and thelike. In some embodiments, the information is read by a processor of thepresent invention. In some such embodiments, the processor configuresother components of the system for use with, or for optimal use with,the component containing the identification element.

In some embodiments, the energy delivery devices have thereon one ormore markings (e.g., scratches, color schemes, etchings (e.g., laseretchings), painted contrast agent markings, identification rings (e.g.,fidicials), and/or ridges) so as to improve identification of aparticular energy delivery device (e.g., improve identification of aparticular device located in the vicinity of other devices with similarappearances). The markings find particular use where multiple devicesare inserted into a patient. In such cases, particularly where thedevices may cross each other at various angles, it is difficult for thetreating physician to associate which proximal end of the device,located outside of the patient body, corresponds to which distal end ofthe device, located inside the patient body. In some embodiments, amarking (e.g., a number) a present on the proximal end of the device sothat it is viewable by the physician's eyes and a second marking (e.g.,that corresponds to the number) is present on the distal end of thedevice so that it is viewable by an imaging device when present in thebody. In some embodiments, where a set of antennas is employed, theindividual members of the set are numbered (e.g., 1, 2, 3, 4, etc.) onboth the proximal and distal ends. In some embodiments, handles arenumbered, a matching numbered detachable (e.g., disposable) antennas areconnected to the handles prior to use. In some embodiments, a processorof the system ensures that the handles and antennas are properly matched(e.g., by RFID tag or other means). In some embodiments, where theantenna are disposable, the system provides a warning if a disposablecomponent is attempted to be re-used, when it should have beendiscarded. In some embodiments, the markings improve identification inany type of detection system including, but not limited to, MRI, CT, andultrasound detection.

The energy delivery systems of the present invention are not limited toparticular types of tracking devices. In some embodiments, GPS and GPSrelated devices are used. In some embodiments, RFID and RFID relateddevices are used. In some embodiments, barcodes are used.

In such embodiments, authorization (e.g., entry of a code, scanning of abarcode) prior to use of a device with an identification element isrequired prior to the use of such a device. In some embodiments, theinformation element identifies that a components has been used beforeand sends information to the processor to lock (e.g. block) use ofsystem until a new, sterile component is provided.

VIII. Temperature Monitoring Systems

In some embodiments, the energy delivering systems of the presentinvention utilize temperature monitoring systems. In some embodiments,temperature monitoring systems are used to monitor the temperature of anenergy delivery device (e.g., with a temperature sensor). In someembodiments, temperature monitoring systems are used to monitor thetemperature of a tissue region (e.g., tissue being treated, surroundingtissue). In some embodiments, the temperature monitoring systems aredesigned to communicate with a processor for purposes of providingtemperature information to a user or to the processor to allow theprocessor to adjust the system appropriately. In some embodiments,temperatures are monitored at several points along the antenna toestimate ablation status, cooling status or safety checks. In someembodiments, the temperatures monitored at several points along theantenna are used to determine, for example, the geographicalcharacteristics of the ablation zone (e.g., diameter, depth, length,density, width, etc.) (e.g., based upon the tissue type, and the amountof power used in the energy delivery device). In some embodiments, thetemperatures monitored at several points along the antenna are used todetermine, for example, the status of the procedure (e.g., the end ofthe procedure). In some embodiments, temperature is monitored usingthermocouples or electromagnetic means through the interstitial antenna.

IX. Procedure Device Hubs

The system of the present invention may further employ one or moreadditional components that either directly or indirectly take advantageof or assist the features of the present invention. For example, in someembodiments, one or more monitoring devices are used to monitor and/orreport the function of any one or more components of the system.Additionally, any medical device or system that might be used, directlyor indirectly, in conjunction with the devices of the present inventionmay be included with the system. Such components include, but are notlimited to, sterilization systems, devices, and components, othersurgical, diagnostic, or monitoring devices or systems, computerequipment, handbooks, instructions, labels, and guidelines, roboticequipment, and the like.

In some embodiments, the systems employ pumps, reservoirs, tubing,wiring, and/or other components that provide materials on connectivityof the various components of the systems of the present invention. Forexample, any type of pump may be used to supply gas or liquid coolantsto the antennas of the present invention. Gas or liquid handling tankscontaining coolant may be employed in the system. In some embodiments,multiple tanks (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, etc.) areused simultaneously, in succession, or as needed. In some embodiments,more than one tank is used such that as one tank becomes empty,additional tanks will be used automatically so as to prevent adisruption in a procedure (e.g., as one CO₂ tank is drained empty, asecond CO₂ tanks is used automatically thereby preventing proceduredisruption). In some embodiments wherein CO₂ is employed, standard Esized CO₂ cylinders are used to supply CO₂.

In some embodiments, the systems employ one or more external heatingdevices. The systems are not limited to a particular use for externalheating devices. In some embodiments, the external heating devices areused to retain certain elements of the system within a particulartemperature range. For example, in some embodiments, external heatingdevices are used to retain gas or liquid handling tanks (e.g., tankscontaining CO₂) providing coolant to one or more devices at within aparticular temperature range. Indeed, in some embodiments, externalheating devices prevent the natural decreasing in temperature a tankundergoes upon release of its contents thereby assuring that the coolantprovided to the device is at a constant temperature or temperaturerange. The systems are not limited to particular external heatingdevices. The external heating devices are not limited to a particularmanner of retaining the temperature within a particular range. In someembodiments, the external heating devices retain the pressure within agas or liquid handling tanks (e.g., tanks containing CO₂) within aparticular range (e.g., heating a tank containing CO₂ (e.g., a standardE sized CO₂ cylinder) at 1000 pounds per square inch so as to retain thepressure as it releases the CO₂ at 850 pounds per square.

In certain embodiments, the energy delivery systems (e.g., the energydelivery device, the processor, the power supply, the imaging system,the temperature adjustment system, the temperature monitoring system,and/or the identification systems) and all related energy deliverysystem utilization sources (e.g., cables, wires, cords, tubes, pipesproviding energy, gas, coolant, liquid, pressure, and communicationitems) are provided in a manner that reduces undesired presentationproblems (e.g., tangling, cluttering, and sterility compromiseassociated with unorganized energy delivery system utilization sources).The present invention is not limited to a particular manner of providingthe energy delivery systems and energy delivery system utilizationsources such that undesired presentation problems are reduced. In someembodiments, as shown in FIG. 13, the energy delivery systems and energydelivery system utilization sources are organized with an import/exportbox 1300, a transport sheath 1310, and a procedure device pod 1320. Insome embodiments, energy delivery systems and energy delivery systemutilization sources organized with an import/export box, transportsheath, and procedure device pod provide several benefits. Such benefitsinclude, but are not limited to, decreasing the number of cordstraversing between a generator (e.g., a microwave generator) and apatient (e.g., decreasing the number of cords on the floor),de-cluttering the sterile environment and procedure room, increasingpatient safety by having the energy delivery systems “move” with apatient thereby preventing device dislodgement (e.g., antennadislodgement), increasing power delivery efficiency by reducing theenergy travel distance within the energy delivery device, and reducingdisposable costs by shortening the length of the disposable cables.

The present invention is not limited to a particular type or kind ofimport/export box. In some embodiments, the import/export box containsthe power supply and coolant supply. In some embodiments, theimport/export box is located outside of a sterile field in which thepatient is being treated. In some embodiments, the import/export box islocated outside of the room in which the patient is being treated. Insome embodiments, the import/export box is located inside of the room inwhich the patient is being treated and maintained in a sterile manner.In some embodiments, one or more cables connect the import/export box toa procedure device pod. In some embodiments, a single cable is used(e.g., a transport sheath). For example, in some such embodiments, atransport sheath contains components for delivery of both energy andcoolant to and/or from the import/export box. In some embodiments, thetransport sheath connects to the procedure device pod without causing aphysical obstacle for medical practitioners (e.g., travels under thefloor, overhead, etc). In some embodiments, the cable is a low-losscable (e.g., a low-loss cable attaching the power supply to theprocedure device hub). In some embodiments, the low-loss cable issecured (e.g., to the procedure device hub, to a procedure table, to aceiling) so as to prevent injury in the event of accidental pulling ofthe cable. In some embodiments, the cable connecting the power generator(e.g., microwave power generator) and the procedure device hub islow-loss reusable cable. In some embodiments, the cable connecting theprocedure device hub to the energy delivery device is flexibledisposable cable. In some embodiments, the cable connecting theprocedure device hub to the energy delivery device has high flexibilitywith “memory” properties (e.g., the cable may be shaped to retain one ormore desired positions). In some embodiments, the cable connecting theprocedure device hub to the energy delivery device is a silicone coveredfiberglass cable.

The present invention is not limited to a particular type or kind ofprocedure device pod. In some embodiments, the procedure device pod isconfigured to receive power, coolant, or other elements from theimport/export box or other sources. In some embodiments, the proceduredevice pod provides a control center, located physically near thepatient, for any one or more of: delivering energy to a medical device,circulating coolant to a medical device, collecting and processing data(e.g., imaging data, energy delivery data, safety monitoring data,temperature data, and the like), and providing any other function thatfacilitates a medical procedure. In some embodiments, the proceduredevice pod is configured to engage the transport sheath so as to receivethe associated energy delivery system utilization sources. In someembodiments, the procedure device pod is configured to receive anddistribute the various energy delivery system utilization sources to theapplicable devices (e.g., energy delivery devices, imaging systems,temperature adjustment systems, temperature monitoring systems, and/oridentification systems). For example, in some embodiments, the proceduredevice pod is configured to receive microwave energy and coolant fromenergy delivery system utilization sources and distribute the microwaveenergy and coolant to an energy delivery device. In some embodiments,the procedure device pod is configured to turn on or off, calibrate, andadjust (e.g., automatically or manually) the amount of a particularenergy delivery system utilization source as desired. In someembodiments, the procedure device pod has therein a power splitter foradjusting (e.g., manually or automatically turning on, turning off,calibrating) the amount of a particular energy delivery systemutilization source as desired. In some embodiments, the procedure devicepod has therein software designed to provide energy delivery systemutilization sources in a desired manner. In some embodiments, theprocedure device pod has a display region indicating associatedcharacteristics for each energy delivery system utilization source(e.g., which devices are presently being used/not used, the temperaturefor a particular body region, the amount of gas present in a particularCO₂ tank, etc.). In some embodiments, the display region has touchcapability (e.g., a touch screen). In some embodiments, the processorassociated with the energy delivery system is located in the proceduredevice pod. In some embodiments, the power supply associated with theenergy delivery systems is located within the procedure device pod. Insome embodiments, the procedure device pod has a sensor configured toautomatically inhibit one or more energy delivery system utilizationsources upon the occurrence of an undesired event (e.g., undesiredheating, undesired leak, undesired change in pressure, etc.). In someembodiments, the weight of the procedure device hub is such that itcould be placed onto a patient without causing discomfort and/or harm tothe patient (e.g., less than 15 pounds, less than 10 pounds, less than 5pounds).

The procedure device pods of the present invention are not limited toparticular uses or uses within particular settings. Indeed, theprocedure device pods are designed for use in any setting wherein theemission of energy is applicable. Such uses include any and all medical,veterinary, and research applications. In addition, the procedure devicepods may be used in agricultural settings, manufacturing settings,mechanical settings, or any other application where energy is to bedelivered. In some embodiments, the procedure device pods are used inmedical procedures wherein patient mobility is not restricted (e.g., CTscanning, ultrasound imaging, etc.).

In some embodiments, the procedure device pod is designed for locationwithin a sterile setting. In some embodiments, the procedure device podis positioned on a patient's bed (e.g., on the bed; on a railing of thebed), a table that the patient is on (e.g., a table used for CT imaging,ultrasound imaging, MRI imaging, etc.), or other structure near thepatient (e.g., the CT gantry). In some embodiments, the procedure devicepod is positioned on a separate table. In some embodiments, theprocedure device pod is attached to a ceiling. In some embodiments, theprocedure device pod is attached to a ceiling such that a user (e.g., aphysician) may move it into a desired position (thereby avoiding havingto position the energy delivery system utilization sources (e.g.,cables, wires, cords, tubes, pipes providing energy, gas, coolant,liquid, pressure, and communication items) on or near a patient while inuse). In some embodiments, the procedure device hub is positioned to layon a patient (e.g., on a patient's legs, thighs, waist, chest). In someembodiments, the procedure device hub is positioned above a patient'shead or below a patient's feet. In some embodiments, the proceduredevice hub has Velcro permitting attachment onto a desired region (e.g.,a procedure table, a patient's drape and/or gown).

In some embodiments, the procedure device hub is configured forattachment to a procedure strap used for medical procedures (e.g., a CTsafety strap). In some embodiments, the procedure strap attaches to aprocedure table (e.g., a CT table) (e.g., through a slot on the sides ofthe procedure table, through Velcro, through adhesive, through suction)and is used to secure a patient to the procedure table (e.g., throughwrapping around the patient and connecting with, for example, Velcro).The procedure device hub is not limited to a particular manner ofattachment with a procedure strap. In some embodiments, the proceduredevice hub is attached to the procedure strap. In some embodiments, theprocedure device hub is attached to a separate strap permittingreplacement of the procedure strap. In some embodiments, the proceduredevice hub is attached to a separate strap configured to attach to theprocedure strap. In some embodiments, the procedure device hub isattached to a separate strap configured to attach to any region of theprocedure table. In some embodiments, the procedure device hub isattached to a separate strap having insulation and/or padding to ensurepatient comfort. FIG. 18 shows a procedure device hub connected to aprocedure table strap.

In some embodiments, the procedure device hub is configured forattachment to a procedure ring. The present invention is not limited toa particular type or kind of procedure ring. In some embodiments, theprocedure ring is configured for placement around a patient (e.g.,around a patient's torso, head, feet, arm, etc.). In some embodiments,the procedure ring is configured to attach to a procedure table (e.g., aCT table). The procedure device ring is not limited to a particularshape. In some embodiments, the procedure device ring is, for example,oval, circular, rectangular, diagonal, etc. In some embodiments, theprocedure device ring is approximately half of a cyclical shape (e.g.,25% of a cyclical shape, 40% of a cyclical shape, 45% of a cyclicalshape, 50% of a cyclical shape, 55 of a cyclical shape, 60 of a cyclicalshape, 75 of a cyclical shape). In some embodiments, the procedure ringis, for example, metal, plastic, graphite, wood, ceramic, or anycombination thereof. The procedure device hub is not limited to aparticular manner of attachment to the procedure ring. In someembodiments, the procedure device hub attaches onto the procedure ring(e.g., with Velcro, with snap-ons, with an adhesive agent). In someembodiments utilizing low-loss cables, the low-loss cables additionalattach onto the procedure ring. In some embodiments, the size of theprocedure ring can be adjusted (e.g., retracted, extended) toaccommodate the size of a patient. In some embodiments, additional itemsmay be attached to the procedure ring. In some embodiments, theprocedure ring may be easily moved to and from the vicinity of apatient.

In some embodiments, the procedure device hub is configured forattachment onto a custom sterile drape. The present invention is notlimited to a particular type or kind of custom sterile drape. In someembodiments, the custom sterile drape is configured for placement onto apatient (e.g., onto a patient's torso, head, feet, arm, entire body,etc.). In some embodiments, the custom sterile drape is configured toattach to a procedure table (e.g., a CT table). The custom sterile drapeis not limited to a particular shape. In some embodiments, the customsterile drape is, for example, oval, circular, rectangular, diagonal,etc. In some embodiments, the shape of the custom sterile drape is suchthat it accommodates a particular body region of a patient. In someembodiments, the procedure ring is, for example, cloth, plastic, or anycombination thereof The procedure device hub is not limited to aparticular manner of attachment to the custom sterile drape. In someembodiments, the procedure device hub attaches onto the custom steriledrape (e.g., with Velcro, with snap-ons, with an adhesive agent, clamps(e.g., alligator clamps)). In some embodiments utilizing low-losscables, the low-loss cables additional attach onto the custom steriledrape. In some embodiments, additional items may be attached to thecustom sterile drape. In some embodiments, the custom sterile drape maybe easily moved to and from the vicinity of a patient. In someembodiments, the custom sterile drape has one more fenestrations forpurposes of performing medical procedures. FIG. 19 shows a customsterile drape with a fenestration and a cable inserted through thefenestration. FIG. 20 shows an energy delivery system of the presentinvention having a generator connected to a procedure device hub via acable, where the procedure device hub is secured to a procedure table(e.g., via a procedure table strap). Moreover, as shown in FIG. 20, acustom sterile drape is positioned over a patient lying on the proceduretable, where the custom sterile drape has a fenestration.

In some embodiments, the procedure device hub is configured with legsfor positioning the hub in the vicinity of a patient. In someembodiments, the procedure device hub has adjustable legs (e.g., therebyallowing positioning of the procedure device hub in a variety ofpositions). In some embodiments, the procedure device hub has threeadjustable legs thereby allowing the device to be positioned in varioustri-pod positions. In some embodiments, the legs have therein Velcropermitting attachment onto a desired region (e.g., a procedure table, apatient's drape and/or gown). In some embodiments, the legs are formedfrom a springy material configured to form an arc over the proceduretable (e.g., CT table) and squeeze the rails of the procedure table. Insome embodiments, the legs are configured to attach onto the rails ofthe procedure table.

In some embodiments, the procedure device pod is configured tocommunicate (wirelessly or via wire) with a processor (e.g., a computer,with the Internet, with a cellular phone, with a PDA). In someembodiments, the procedure device hub may be operated via remotecontrol. In some embodiments, the procedure device pod has thereon oneor more lights. In some embodiments, the procedure device hub provides adetectable signal (e.g., auditory, visual (e.g., pulsing light)) whenpower is flowing from the procedure device hub to an energy deliverydevice. In some embodiments, the procedure device hub has an auditoryinput (e.g., an MP3 player). In some embodiments, the procedure devicehub has speakers for providing sound (e.g., sound from an MP3 player).In some embodiments, the procedure device hub has an auditory output forproviding sound to an external speaker system. In some embodiments, theuse of a procedure device pod permits the use of shorter cables, wires,cords, tubes, and/or pipes (e.g., less than 4 feet, 3 feet, 2 feet). Insome embodiments, the procedure device pod and/or one more componentsconnected to it, or portions thereof are covered by a sterile sheath. Insome embodiments, the procedure device hub has a power amplifier forsupplying power (e.g., to an energy delivery device).

In some embodiments, the procedure device pod is configured to compresstransported coolants (e.g., CO₂) at any desired pressure so as to, forexample, retain the coolant at a desired pressure (e.g., the criticalpoint for a gas) so as to improve cooling or temperature maintenance.For example, in some embodiments, a gas is provided at or near itscritical point for the purpose of maintaining a temperature of a device,line, cable, or other component at or near a constant, definedtemperature. In some such embodiments, a component is not cooled per se,in that its temperature does not drop from a starting temperature (e.g.,room temperature), but instead is maintained at a constant temperaturethat is cooler than where the component would be, but for theintervention. For example, CO₂ may be used at or near its critical point(e.g., 31.1 Celsius at 78.21 kPa) to maintain temperature so thatcomponents of the system are sufficiently cool enough not to burntissue, but likewise are not cooled or maintained significantly belowroom temperature or body temperature such skin in contact with thecomponent freezes or is otherwise damaged by cold. Using suchconfigurations permits the use of less insulation, as there are not“cold” components that must be shielded from people or from the ambientenvironment. In some embodiments, the procedure device pod has aretracting element designed to recoil used and/or unused cables, wires,cords, tubes, and pipes providing energy, gas, coolant, liquid,pressure, and/or communication items. In some embodiments, the proceduredevice pod is configured to prime coolants for distribution into, forexample, an energy delivery device such that the coolant is at a desiredtemperature prior to use of the energy delivery device. In someembodiments, the procedure device pod has therein software configured toprime coolants for distribution into, for example, an energy deliverydevice such that the system is at a desired temperature prior to use ofthe energy delivery device. In some embodiments, the circulation ofcoolants at or near critical point permits cooling of the electronicelements of the energy delivery devices without having to use additionalcooling mechanisms (e.g., fans).

In one illustrative embodiment, an import/export box contains one ormore microwave power sources and a coolant supply (e.g., pressurizedcarbon dioxide gas). This import/export box is connected to a singletransport sheath that delivers both the microwave energy and coolant toa procedure device pod. The coolant line or the energy line within thetransport sheath may be wound around one another to permit maximumcooling of the transport sheath itself The transport sheath is run intothe sterile field where a procedure is to take place along the floor ina location that does not interfere with the movement of the medical teamattending to the patient. The transport sheath connects to a tablelocated near an imaging table upon which a patient lays. The table isportable (e.g., on wheels) and connectable to the imaging table so thatthey move together. The table contains arm, which may be flexible ortelescoping, so as to permit positioning of the arm above and over thepatient. The transport sheath, or cables connected to the transportsheath, run along the arm to the overhead position. At the end of thearm is the procedure device pod. In some embodiments, two or more armsare provided with two or more procedure device pods or two or moresub-components of a single procedure device pod. The procedure devicepod is small (e.g., less than 1 foot cube, less than 10 cm cube, etc.)to allow easy movement and positioning above the patient. The proceduredevice pod contains a processor for controlling all computing aspects ofthe system. The device pod contains one or more connections ports forconnecting cables that lead to energy delivery devices. Cables areconnected to the ports. The cables are retractable and less than threefeet in length. Use of short cables reduces expense and prevents powerloss. When not in use, the cables hang in the air above the patient, outof contact with the patient's body. The ports are configured with adummy load when not in use (e.g., when an energy delivery device is notconnected to a particular port). The procedure device pod is withinreach of the treating physician so that computer controls can beadjusted and displayed information can be viewed, in real-time, during aprocedure.

In some embodiments, the energy delivery systems utilize procedure cartsfor maintaining system elements within one area. For example, in someembodiments, the systems provide a procedure cart that is configured tostore the cooling supply (e.g., multiple tanks supplying gas or liquidcoolant to the devices of the present invention) (e.g., standard E sizedCO₂ cylinders) for device cooling purposes, external heating devices tomaintain the coolant supply at desired pressures, one or more powersupplies, one or more related energy delivery system utilization sources(e.g., cables, wires, cords, tubes, pipes providing energy, gas,coolant, liquid, pressure, and communication items), and/or theprocedure device hub. Indeed, the procedure cart is not limited to aparticular design or purpose. In some embodiments, the procedure cart isconfigured for use within a sterile setting (e.g., a procedure room) andhas therein cooling tanks, related external heating devices, and aprocedure device pod/hub. In some embodiments, the procedure cart isconfigured for non-sterile settings only. In some embodiments, theprocedure cart is configured for easy movement (e.g., it is designedwith wheels). The procedure cart is configured to connect with anycomponent of the energy delivery systems of the present invention (e.g.,the import/export box, the transport sheath, and/or the procedure devicehub). In some embodiments, the procedure cart has therein a displayregion for operating and/or monitoring the components of the energydelivery systems (e.g., user interface software). In some embodiments,the procedure cart is configured to communicate (wirelessly or via wire)with a processor (e.g., a computer, with the Internet, with a cellularphone, with a PDA). In some embodiments, the procedure cart isconfigured to send and receive information (wirelessly or via wire)pertaining to the energy delivery systems (e.g., the number of uses foreach component, which devices are being used, etc.).

X. Uses for Energy Delivery Systems

The systems of the present invention are not limited to particular uses.Indeed, the energy delivery systems of the present invention aredesigned for use in any setting wherein the emission of energy isapplicable. Such uses include any and all medical, veterinary, andresearch applications. In addition, the systems and devices of thepresent invention may be used in agricultural settings, manufacturingsettings, mechanical settings, or any other application where energy isto be delivered.

In some embodiments, the systems are configured for open surgery,percutaneous, intravascular, intracardiac, endoscopic, intraluminal,laparoscopic, or surgical delivery of energy. In some embodiments, theenergy delivery devices may be positioned within a patient's bodythrough a catheter, through a surgically developed opening, and/orthrough a body orifice (e.g., mouth, ear, nose, eyes, vagina, penis,anus) (e.g., a N.O.T.E.S. procedure). In some embodiments, the systemsare configured for delivery of energy to a target tissue or region. Insome embodiments, a positioning plate is provided so as to improvepercutaneous, intravascular, intracardiac, laparoscopic, and/or surgicaldelivery of energy with the energy delivery systems of the presentinvention. The present invention is not limited to a particular typeand/or kind of positioning plate. In some embodiments, the positioningplate is designed to secure one or more energy delivery devices at adesired body region for percutaneous, intravascular, intracardiac,laparoscopic, and/or surgical delivery of energy. In some embodiments,the composition of the positioning plate is such that it is able toprevent exposure of the body region to undesired heat from the energydelivery system. In some embodiments, the plate provides guides forassisted positioning of energy delivery devices. The present inventionis not limited by the nature of the target tissue or region. Usesinclude, but are not limited to, treatment of heart arrhythmia, tumorablation (benign and malignant), control of bleeding during surgery,after trauma, for any other control of bleeding, removal of soft tissue,tissue resection and harvest, treatment of varicose veins, intraluminaltissue ablation (e.g., to treat esophageal pathologies such as Barrett'sEsophagus and esophageal adenocarcinoma), treatment of bony tumors,normal bone, and benign bony conditions, intraocular uses, uses incosmetic surgery, treatment of pathologies of the central nervous systemincluding brain tumors and electrical disturbances, sterilizationprocedures (e.g., ablation of the fallopian tubes) and cauterization ofblood vessels or tissue for any purposes. In some embodiments, thesurgical application comprises ablation therapy (e.g., to achievecoagulative necrosis). In some embodiments, the surgical applicationcomprises tumor ablation to target, for example, metastatic tumors. Insome embodiments, the device is configured for movement and positioning,with minimal damage to the tissue or organism, at any desired location,including but not limited to, the brain, neck, chest, abdomen, andpelvis. In some embodiments, the systems are configured for guideddelivery, for example, by computerized tomography, ultrasound, magneticresonance imaging, fluoroscopy, and the like.

In certain embodiments, the present invention provides methods oftreating a tissue region, comprising providing a tissue region and asystem described herein (e.g., an energy delivery device, and at leastone of the following components: a processor, a power supply, atemperature monitor, an imager, a tuning system, and/or a temperaturereduction system); positioning a portion of the energy delivery devicein the vicinity of the tissue region, and delivering an amount of energywith the device to the tissue region. In some embodiments, the tissueregion is a tumor. In some embodiments, the delivering of the energyresults in, for example, the ablation of the tissue region and/orthrombosis of a blood vessel, and/or electroporation of a tissue region.In some embodiments, the tissue region is a tumor. In some embodiments,the tissue region comprises one or more of the heart, liver, genitalia,stomach, lung, large intestine, small intestine, brain, neck, bone,kidney, muscle, tendon, blood vessel, prostate, bladder, and spinalcord.

EXPERIMENTAL Example I

This example demonstrates the avoidance of undesired tissue heatingthrough use of an energy delivery device of the present inventioncirculating coolant through coolant channels. The ablation needle shaftfor all experiments was 20.5 cm. There was minimal cooling of the handleassembly indicating that handle-cooling effects were well-isolated.Temperature probes 1, 2 and 3 were located at 4, 8 and 12 cm proximal tothe tip of the stainless needle (see FIG. 9). Temperature measurementswere taken for 35% power measurement following insertion into a pigliver and 45% power measurement following insertion into a pig liver.For the 35% power measurement, Probe 4 was on the handle itself. For the45% power measurements, Probe 4 was located at the needle-skininterface, approximately 16 cm back from the stainless needle tip.

As shown in FIG. 10, treatment at 35% power for 10 minutes withanonymously high (6.5%) reflected power demonstrated maintenance of thedevice at a non-tissue damaging temperature at Probes 1, 2, 3 and thehandle.

As shown in FIG. 11, treatment at 45% power for 10 minutes withanonymously high (6.5%) reflected power demonstrated maintenance of thedevice at a non-tissue damaging temperature at Probes 1, 2, 3 and 4.Observation of the skin and fat layers after 10 minutes ablation at 45%power for 10 minutes with anonymously high (6.5%) reflected powerdemonstrating no visible burns or thermal damage.

Example II

This example demonstrates generator calibration. Generator calibrationwas done by Cober-Muegge at the factory and was set to be most accuratefor powers greater than 150 W. The magnetron behaved much like a diode:increasing cathode voltage did not increase vacuum current (proportionalto output power) until a critical threshold was reached, at which pointvacuum current increased rapidly with voltage. Control of the magnetronsource relied on accurate control of the cathode voltage near thatcritical point. As such, the generator was not specified for powers from0-10% and correlation between the output power and theoretical powerpercentage input was poor below 15%.

To test the generator calibration, the power control dial was changedfrom 0.25% in 1% increments (corresponding to theoretical output powersof 0-75 W in 3 W increments) and the generator's output power displaywas recorded and power output measured. The measured power output wasadjusted for the measured losses of the coaxial cable, coupler and loadat room temperature. The output display was also adjusted for offseterror (i.e., the generator read 2.0% when the dial was set to 0.0%).

The error between the dial and generator output power display was largefor low-power dial settings. These two values quickly converged to apercent error of less than 5% for dial settings above 15%. Similarly,the measured output power was significantly different from thetheoretical output power for dial settings below 15% but more accuratefor dial settings above 15%.

Example III

This example describes the setup and testing of an antenna duringmanufacturing. This provides a method for setup and tested in amanufacturing environment. The method employs a liquid,tissue-equivalent phantom rather than tissue.

From the numerical and experimental measurements already made on theantenna, it was known that changes in L2 of ˜1 mm will increase thereflected power from <−30 dB to ˜−20-25 dB. This increase was likelymade less significant by the changes in tissue properties that occurredduring ablation and so we would consider at relative tolerance of 0.5 mmon the length L2 is reasonable. Likewise, a tolerance of 0.5 mm on thelength L1 is used, even though the total reflection coefficient dependsless on L1 than L2.

Testing of the antenna tuning for quality control purposes can beachieved using a liquid 15 solution designed to mimic the dielectricproperties of liver, lung or kidney (see, e.g., Guy A W (1971) IEEETrans. Microw. Theory Tech. 19:189-217; herein incorporated by referencein its entirety). The antenna is immersed in the phantom and thereflection coefficient recorded using a 1-port measurement device orfull vector network analyzer (VNA). Verification of a reflectioncoefficient below −30 dB is selected to ensure proper tuning.

Example IV

This example compared the efficiency, heating ability, andmanufacturability of the triaxial and center-fed dipole antennas.Modification of the original triaxial design was required to create amore rigid, sharp tip that could be easily inserted. Computer modelingwas initially used to determine what changes in antenna length might berequired with the addition of an alumina sheath and faceted metallictip. After modeling confirmed that the antenna would need to belengthened and the metallic tip would not degrade performance, antennaswere constructed for testing in ex vivo liver tissue. This testingshowed that the modified design retained its high efficiency whileproviding enough mechanical strength for percutaneous placement.Computer modeling of the center-fed dipole design yielded marginalresults and subsequent device fabrication proved difficult to reproduce.Accordingly, the insertable triaxial device was chosen as a lead antennadesign.

Computer modeling revealed that both thermally-resistive coatings andserious thermal breaks can reduce the amount of heat that is allowed toflow from the distal antenna tip to proximal sections of the antenna.However, an effective water cooling solution was able to increase thepower throughput of a 0.020″ coaxial cable from ˜8 W to over 150 W.Water cooling also eliminated any shaft heating extending proximallyfrom the antenna tip when using 150 W input power (FIG. 21). However,implementation required the use of expensive 0.020″ coaxial cable toprovide sufficient water flow rates (−30 ml/min). In addition, 0.020″cable is 2-3× more lossy than the 0.047″ cable used previously, whichdecreased power throughput by as much as 15 W and required cooling ofthat additional power loss. The final antenna design incorporated a PEEKsheath around the entire assembly to reduce sticking that can occurbetween a metallic antenna and surrounding tissue while also providingthe thermal buffer shown to reduce thermally conductive heating.

A study was performed percutaneously using either the cooled, 17-gaugeprototype antenna or 17-gauge cooled RF electrode fromValleylab/Covidien to create ablations in a normal, in vivo porcine lungmodel. Ablations were performed for 10 min using the clinical standardof 200 W with impedance control for RF and 135 W for the microwavegroup. Ablations created in the microwave group were significantlylarger than in the RF group with a mean ablation diameter (mean±standarddeviation) of 3.32±0.19 cm and 2.7±0.27 cm, respectively (P<0.0001, FIG.9). Ablation circularity was also significantly higher in the microwavegroup than in the RF group (0.90±0.06 vs. 0.82±0.09, P<0.05). No majorcomplications were observed throughout the entire study. Minorpneumothoraces were observed in one animal during two ablations, bothfrom the RF group. Both remained stable without intervention. From thisstudy, it was concluded that microwaves are more effective and typicallyfaster than RF current for heating lung tissue.

Example V

This example investigated cooling in a simulated heating environment. Aheater coil was passed through a 17-gauge stainless needle nearlyidentical to the third conductor of the triaxial antenna. Fourthermocouples were placed along the outside of the needle and the entiresystem thermally isolated with closed-cell foam. This setup wasconsidered worst-case, since blood flow and the high thermalconductivity of biological tissues will tend to provide some antennacooling. The coil was heated with 0-50 W and temperatures recorded withNC-CO₂ operating at 0-10 stp L/min flow rates. Test results showed thata moderate flow of CO2 was sufficient to cool the entire 50 W inputpower so that the heated tube remained at ambient temperature (FIG. 24).

Temperatures recorded on the outer surface of the needle without coolingpresent exceeded 100° C., but cooling with 10-20 stp L/min of NC-CO₂reduced the surface temperature to below 30° C. (FIG. 24). These testsshowed that moderate amounts of NC-CO₂ (−10 stp L/min) can effectivelycool as much as 50 W from the inside of an ablation antenna.

Example VI

This experiment measured the effects of thermal conduction proximallyfrom the heated antenna tip. A modified antenna—with the ceramicradiating segment replaced with a thermally-conductive copper tube—wasplaced into an electric heater with thermal paste to ensure a goodthermal contact between the heater and antenna (FIG. 25). Thermocoupleswere placed along the outer surface of the antenna at several points tomeasure temperature versus NC-CO₂ flow rate.

Before cooling, temperatures along the outer conductor exceeded 80° C. 1cm proximal to the heater. When cooling was initiated even at a modestrate of 13 stp L/min, temperatures dropped to the input temperature ofthe NC-CO₂ gas: ˜0° C. (FIG. 25). Increasing the flow rate decreasedtemperatures even further. Gas was precooled slightly in aheat-exchanger to test the possibility of a “stick” function on theneedle shaft, similar to that employed by cryoablation probes. Thisprecooling led to the lower-than-required temperature of 31° C. fornear-critical operation and additional implementation was beyond thescope of this investigation.

Follow-up tests using the same setup and heater was also performed toevaluate the lower-limit of cooling power required. In this study, aninitial flow of 10 stp L/min was shown to decrease temperatures to ˜0°C. That flow was then removed and pulses of CO₂ at 1 stp L/min wereinjected for approximately 10 s when the shaft temperature rose morethan 30° C. Despite rapid rises in temperature without cooling, onlysmall pulses of CO₂ were required to eliminate temperature rise and keepthe system at ambient temperature (FIG. 26). These results suggest, forexample, that small amounts of CO₂ may be able to be used to keep theantenna below ISO 60601-1 standards during the procedure. A temperaturefeedback/monitoring system could be employed to minimize the use of CO₂during the procedure. Near-critical CO₂ is a feasible and effectivealternative to liquid cooling inside microwave ablation antennas. Theincreased heat capacity of NC-CO₂ ensures that only small volumes offluid are required to cool the ablation antenna to safe levels. It wasshown that modest flow rates ˜10 stp L/min were sufficient to coolantennas generating as much as 50 W.

Example VII

This example assessed the feasibility of using small, periodicinjections of iodinated contrast material over the course of theablation with a new reconstruction technique to improve ablation zonevisualization while reducing contrast material dose. The lack of aubiquitous and effective intra-procedural imaging technique is acritical limitation to the field of thermal tumor ablation. Ultrasoundimaging can be obscured by bubbles formed while heating, andcontrast-enhanced CT is typically limited to one scan with a largeinjection of contrast material.

Female domestic swine were prepared and anesthetized. RF ablation wasperformed for 20 min using three internally-cooled, switched electrodes.During ablation, 15 ml iodinated contrast material (300 mg/ml) wasdelivered every 2 min and an abdominal CT collected at thepre-determined liver enhancement time following each injection (90 s).CT images were created using both conventional online reconstruction andoffline reconstruction with HighlY-constrained backPRojection (HYPR).Conventional and HYPR-reconstructed images were compared for imagingcontrast between the ablation zone and background liver and signal tonoise ratios.

Ablation zone growth was able to be visualized with 2 min temporalresolution. The ablation zone became readily apparent in 2-6 min with acumulative contrast dose of 15-45 ml. Image quality improved withcumulative contrast dose. SNR in HYPR-reconstructed images was ˜3-4×better than standard reconstructions and HYPR improved signal contrastbetween the ablation zone and background liver by up to 6× (FIGS. 27 and28).

All publications and patents mentioned in the above specification areherein incorporated by reference. Various modifications and variationsof the described method and system of the invention will be apparent tothose skilled in the art without departing from the scope and spirit ofthe invention. Although the invention has been described in connectionwith specific embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments.Indeed, various modifications of the described modes for carrying outthe invention that are obvious to those skilled in the relevant fieldsare intended to be within the scope of the following claims.

We claim:
 1. A microwave ablation device comprising a proximal region, acentral region and a distal region, the distal region comprising anantenna configured to deliver microwave ablation energy, at least onestick region positioned within said central region and/or the proximalregion and configured to attain and maintain a temperature causingfreezing of tissue to facilitate adhering of the tissue to the stickregion in order to stabilize the microwave ablation device in a desiredposition with respect to a tissue region during microwave ablation, anda seal positioned between the stick region and the distal region therebypreventing exposure of the stick region to the distal region.
 2. Theablation device of claim 1, wherein the ablation device furthercomprises one or more coolant tubes or channels configured to delivercoolant to the stick region and/or the antenna.
 3. The ablation deviceof claim 1, wherein the antenna comprises a coaxial transmission line.4. The ablation device of claim 1, wherein the antenna comprises atri-axial antenna transmission line.
 5. The ablation device of claim 1,wherein the distal region and central region are separated by a plugregion.
 6. The ablation device of claim 5, wherein the plug region isconfigured to prevent cooling of the distal region resulting fromcooling of the central region.